Snow Geese, Bald Eagles, and More at Middle Creek Wildlife Management Area

To take advantage of this unusually mild late-winter day, observers arrived by the thousands to have a look at an even greater number of migratory birds gathered at the Pennsylvania Game Commission’s Middle Creek Wildlife Management Area.  Here are some highlights…

Trails at Middle creek Wildlife Management Area
Multitudes of Sunday hikers enjoyed the warm afternoon on Middle Creek’s many trails.
Painted Turtles
In one of Middle Creek’s numerous impoundments, newly emerged Painted Turtles bask in the sunshine.
Brown-headed Cowbird
Native blackbirds, particularly males including this Brown-headed Cowbird, are arriving to stake out a claim on suitable breeding territory.
Red-winged Blackbirds
Male Red-winged Blackbirds visit the feeding station at the Middle Creek W.M.A. Visitor’s Center.
Brown-headed Cowbird and Red-winged Blackbird
Brown-headed Cowbirds regularly maintain close association with Red-winged Blackbirds, a frequent victim of the former’s nest parasitism, the practice of laying and abandoning their eggs in a host species’ abode.  By early May, adult “red-wings” can often be seen tending fledged cowbird young raised at the expense of their own progeny.
Common Grackles displaying.
Male Common Grackles display their colors in an attempt to establish dominance.
White-crowned Sparrow
Visitor’s to Middle Creek’s Willow Point Trail not only had a chance to see thousands of geese and other waterfowl, but they might also get a good look at some of the handsome White-crowned Sparrows that have been there during recent weeks.
Tree Swallow
The first Tree Swallows of the season have arrived to stake a claim to nest boxes located throughout the refuge’s grasslands.
Killdeer
Bare croplands and muddy shorelines around Middle Creek’s lakes and ponds are attracting migrating Killdeer.  Some will stay to nest.
Ring-billed Gulls
Hundreds of Ring-billed Gulls arrived during the late afternoon to spend the night on the main lake.
Red-tailed Hawk
A Red-tailed Hawk was seen hunting mice and exhibiting territorial behavior.  It is probably protecting a nest site somewhere on the refuge.
Canada Geese
Canada Geese could be seen coming and going, with migratory birds apparently supplementing the resident flock.  This group flushed when a Bald Eagle passed close by.
Bald Eagles
You could hold a Bald Eagle I.D. clinic at Middle Creek W.M.A. right now.  Dozens of birds of varying age classes could be seen in the trees surrounding the main lake and the larger ponds.  Currently, fifty or more could be present.  At least one Golden Eagle has been seen as well.
Adult Bald Eagle
An adult Bald Eagle in definitive plumage investigating the inhabitants of the lake.
Second-year Bald Eagle
This Bald Eagle in its second calendar year is not yet one year of age, but it has already begun replacing dark body feathers with a light plumage that will earn it the nickname “white belly” for this and its third year.  It will start molting its long hatch-year (juvenile) flight feathers soon after its first birthday.
Second-year Bald Eagle and Red-tailed Hawk
Another second-year immature Bald Eagle, this one being scolded by the aforementioned territorial Red-tailed Hawk.  Though showing some wear in the tail, this eagle still has a full set of lengthy hatch-year (juvenile) flight feathers and remains mostly dark below when compared to the bird of the same age class seen in the previous image.  As in other birds, diet, genetics, stress, climatic conditions, and many other factors will frequently vary the timing of molt among individuals in a population of Bald Eagles.
Third-year Bald Eagle
An immature Bald Eagle in its third calendar year still retaining numerous long juvenile wing and tail feathers.   In coming months, as it reaches its second birthday, it will begin replacing the remaining older plumage with a set of new flight feathers.
Fourth-year Bald Eagle
An immature Bald Eagle in its fourth calendar year approaches its third birthday with a rather conspicuous long juvenile feather remaining in each wing.  These feathers will soon be replaced.  In addition, the body plumage will darken, the head will begin to show more white, and the bill will become yellow.  In about two more years, the bird will attain its familiar adult definitive plumage.  Click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab at the top of this page to learn more about determining the age of these and other birds of prey.
Snow Geese and Observers at Middle Creek W.M.A.
Bald Eagles draw a crowd, but the real attraction at Middle Creek W.M.A. in late winter is Snow Geese,…
Snow Geese
…thousands of them.
Snow geese at Middle Creek W.M.A.
Migratory Snow Geese, an annual spectacle at Middle Creek.
Snow Geese and hundreds of onlookers.
Snow Geese and hundreds of delighted onlookers.

Snow Geese at M.C.W.M.A.

Snow geese at Middle Creek W.M.A.
The late afternoon sky filled with Snow Geese.
Short-eared Owl at M.C.W.M.A.
As daylight waned and the Snow Geese returned to the main lake for the night, more than one hundred lucky observers were treated to the rare sight of several Short-eared Owls (Asio flammeus) emerging to hunt the refuge’s managed grasslands for mice and voles.  For many of these visitors, it was a memorable first-time experience.

It’s Bald Eagle Time, Wherever You Are

Now is a great time of year to see Bald Eagles in the Lower Susquehanna River Watershed.  For the population that breeds here in our region, it’s nesting season.  These birds are defending territories and some of them can get pretty aggressive towards the other eagles that happen to be wintering in the Susquehanna valley or will be migrating north through the area in coming weeks.  All that competition has these birds spending a lot of time in the air, so no matter where you happen to be, keeping an eye on the sky may provide you with an opportunity for a memorable glimpse of one or more eagles in action.  Skeptical?  Well, just an hour ago, we spotted these eagles high above the susquehannawildlife.net headquarters garden.

So do spend some time outdoors soon and while you’re there, don’t forget to look up.  You might turn some of your time into Bald Eagle time too!

Migrating Ducks Find Emergency Refuge on the Susquehanna

As anticipated, lakes and ponds throughout the lower Susquehanna basin are beginning to freeze.  Fortunately for the waterfowl thereon, particularly diving ducks, the rain-swollen river is slowly receding and water clarity is improving to provide a suitable alternative to life on the man-made impoundments.

Ice-free Susquehanna at Harrisburg, Pennsylvania
The Susquehanna, ice-free and receding from near flood stage levels last week, can presently provide suitable habitat for diving ducks and other wintering waterfowl.
A Common Merganser on the Susquehanna in Dauphin County, Pennsylvania.
A feeding Common Merganser takes a breather between dives on the Susquehanna in Dauphin County, Pennsylvania.

The deep freeze is not only impacting ponds and lakes in the lower Susquehanna valley, but is evidently affecting the larger bodies of water to our north and northwest.  During Tuesday’s snow event, thousands of diving ducks arrived on the main stem of the river—apparently forced down by the inclement weather while en route to the Atlantic Coast from the Great Lakes and its connected waterways, which are currently beginning to freeze.

Ice-free Susquehanna
Tuesday’s snowfall not only blanketed the landscape with a coating of white,…
Bay Ducks on the Susquehanna
…it prompted thousands of migrating “bay ducks” including Canvasbacks, Redheads, scaup, and other diving species to seek open water and make a forced landing.
Scaup on the Susquehanna
Scaup were by far the most numerous of the birds in the grounded flight.  The majority appeared to be Lesser Scaup.
Scaup in flight.
Scaup in flight on the Susquehanna.
Scaup, Buffleheads, and Long-tailed Duck
A mixed raft of scaup and Buffleheads seen one day after a snowstorm-related fallout of late-season migrants.  A single Long-tailed Duck, a species formerly known as Oldsquaw, can be seen to the lower left.
Scaup, Bufflehead, and Long-tailed Duck
Scaup and a Bufflehead (center) fly past a Long-tailed Duck.  Because they winter primarily in coastal waters, both of the latter species are sometimes categorized as “sea ducks”.
Ruddy Ducks
A small flock of Ruddy Ducks.
Common Mergansers
While Common Mergansers on the Susquehanna are fish eaters (piscivores), other diving ducks observed during this fallout event are primarily benthic feeders, eating plant matter and invertebrate animals collected from the river bottom.
Common Goldeneyes
A small flock of Common Goldeneyes. They, like the Long-tailed Duck and Bufflehead, are sometimes known as a species of “sea duck”.
Scaup and Buffleheads
Another mixed raft of scaup and Buffleheads loafing on the Susquehanna.
Bald Eagle
Large numbers of waterfowl attract the attention of the river’s ever-vigilant Bald Eagles.
Adult Bald Eagle
An adult Bald Eagle patrolling the area of a fallout in search of dead, sick, or injured ducks.  In addition to the victims of naturally occurring ailments, eagles find birds and mammals wounded or killed by hunters to be particularly attractive sources of food.   They can, therefore, quite easily ingest pieces of shot.  Because eagles in the lower Susquehanna valley feed as frequently in upland habitats as they do in riverine environs, use of alternatives to toxic lead shot is prudent practice in all habitat types.
Fourth-year Bald Eagle
A Bald Eagle in the first month of its fourth calendar year.   Though not yet matured to breeding age, this bird is nevertheless smart enough to be on the lookout for vulnerable or deceased waterfowl during a post-storm fallout.
Seeing Some Waterfowl
A fallout of some migrating waterfowl seldom escapes notice by members of the gasoline and gunpowder gang…
Taking Aim at Some Waterfowl
…who find their very presence an irresistible temptation to arouse their adolescent urges…
Harrassing Some Waterfowl
…to get an adrenaline junkie’s fix.

With more snow on the way for tomorrow, you may be wondering if another fallout like this could be in the works.  The only way to find out is to get out there and have a look.  Good luck!  And be good!

Photo of the Day

Bald Eagle
The last of the year’s migrating Bald Eagles are streaming down the ridges of the mid-Atlantic region and many of them will be stopping for at least a part of the winter season along the lower Susquehanna River.  If you want to see them, now is the best time.  Taking a walk along a riverside recreation trail is a relaxing way to spend some time checking them out.  To see the greatest concentrations of these majestic birds, plan a visit to one of the lower river’s hydroelectric dams.  Conowingo Dam, located where U.S. Route 1 crosses the river at Rising Sun, Maryland, is currently hosting dozens of visiting eagles.  If you’ve never been there, we can assure you that it’s certainly worth the trip.

Big Winds Bring Big Birds

Colder temperatures and gusty northwest winds are prompting our largest migratory raptors to continue their southward movements.  Here are some of the birds seen earlier today riding updrafts of air currents along one of the Lower Susquehanna River Watershed’s numerous ridges.

Turkey Vulture
Hundreds of Turkey Vultures are presently passing through the lower Susquehanna valley on their way south.  Their winter abundance here is largely determined by the availability of carrion.
Hatch-year Bald Eagle
The late-season push of Bald Eagles is now underway.  Today, ten or more birds were seen at several of the region’s hawk watches.  This particular eagle is a juvenile, a hatch-year bird, with an unusually large area of white in the tail.
Red-tailed Hawks
Red-tailed hawks pass a hawk-counting station while gliding away to the southwest within an energy-saving updraft of ridge-deflected wind.
Golden Eagle and Red-shouldered Hawk
A migrating Golden Eagle keeps a wary eye on a marauding Red-shouldered Hawk.  This Golden Eagle is young, either in its hatch year or second year of life.
Red-tailed Hawk
A Red-tailed Hawk migrating during a late-afternoon snow shower.

As winter begins clawing at the door, now is great time to visit a hawk watch near you to see these late-season specialties.  Remember to dress in layers and to click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab at the top of this page.  Hawkwatcher’s Helper is your guide to regional hawk watching locations and raptor identification.  Be sure to check it out.  And remember, it’s cold on top of those ridges, so don’t forget your hat, your gloves, and your chap stick!

This Week at Regional Hawk Watches

With nearly all of the Neotropical migrants including Broad-winged Hawks gone for the year, observers and counters at eastern hawk watches are busy tallying numbers of the more hardy species of diurnal raptors and other birds.  The majority of species now coming through will spend the winter months in temperate and sub-tropical areas of the southern United States and Mexico.

Here is a quick look at the raptors seen this week at two regional counting stations: Kiptopeke Hawk Watch near Cape Charles, Virginia, and Second Mountain Hawk Watch at Fort Indiantown Gap, Pennsylvania.

Kiptopeke Hawk Watch
The hawk-watching platform at Kiptopeke State Park is located along Chesapeake Bay near the southern tip of Delmarva Peninsula.  In autumn, thousands of raptors and other birds migrate through the Atlantic Coastal Plain Province.  Those that follow the shorelines south frequently concentrate in spectacular numbers before crossing the mouths of the bays they encounter.  This phenomenon makes both Cape May, New Jersey, on Delaware Bay and Kiptopeke, Virginia, on Chesapeake Bay exceptional places to experience fall flights of migrating birds.
Second Mounatin Hawk Watch
A Sharp-shinned Hawk is counted as it swoops by the owl decoy at Second Mountain Hawk Watch at Fort Indiantown Gap Military Reservation.  Migrating raptors save energy by riding updrafts of air created by winds blowing against the slopes of the mountainsides in the Ridge and Valley Province.
Sharp-shinned Hawk
A Sharp-shinned Hawk passes the lookout at Second Mountain Hawk Watch.  “Sharp-shins” are currently the most numerous migrants both on the coast and at inland counting stations.
Sharp-shinned Hawk
A Sharp-shinned Hawk nearly passes observers unnoticed as it skims the treetops.
Sharp-shinned Hawk at owl decoy.
A Sharp-shinned Hawk eyes up an owl decoy.  Under cover of darkness, nocturnal owls could rather easily prey upon young and small adult hawks and falcons, both on the nest or at roost.  Accordingly, many diurnal raptors instinctively harass owls to drive them from their presence.  An owl decoy at the lookout helps attract migrating birds for a closer look.
Cooper's Hawk
An adult Cooper’s Hawk flaps its way past a counting station.  Like the similar Sharp-shinned Hawk, the larger Cooper’s Hawk is a member of the genus Accipiter.  As a proportion of the annual fall Accipiter flight, the Cooper’s Hawk is more numerous at coastal hawk watches than at inland sites.
Osprey
The majority of Osprey migrate along the coast, but a few are still being seen at inland hawk watches.
Bald Eagle
Bald Eagles are commonly seen at both coastal and inland lookouts.  Their movements continue well into late fall.
Northern Harrier
A Northern Harrier illuminated by a setting sun.  Northern Harriers are often still flying when many other species have gone to roost for the day.
An adult male Northern Harrier flying in misty weather.
An adult male Northern Harrier, the “gray ghost”, flying in misty weather, at a time when few other birds were in the air. 
American Kestrel
The American Kestrel, like our other falcons, is seen in greatest concentrations at coastal counting stations.  It is our most numerous falcon.
Merlin
The Merlin provides only a brief observation opportunity as it passes the lookout.  These falcons are dark, speedy, and easily missed as they fly by.
Tree Swallow
While moving south, Merlins often accompany flights of migrating Tree Swallows, a potential food source.
Merlin with Dragonfly
A Merlin consumes a dragonfly.  Eating is no reason to stop moving.
Juvenile "Tundra Peregrine"
The “Tundra Peregrine” is an arctic-breeding Peregrine Falcon that travels a distance of over 6,000 miles to southern South America for winter.  It is strictly a migratory species in our region with numbers peaking during the first two weeks of October each year.  These strong fliers have little need for the updrafts from mountain ridges, inland birds often observed flying in a north to south direction.  The majority of “Tundra Peregrines” are observed following coastlines, with some migrating offshore to make landfall at points as far south as Florida and the Caribbean islands before continuing across water again to reach the northern shores of Central and South America.  This “Tundra Peregrine” is a juvenile bird on its first southbound trip.

During coming days, fewer and fewer of these birds will be counted at our local hawk watches.  Soon, the larger raptors—Red-tailed Hawks, Red-shouldered Hawks, and Golden Eagles—will be thrilling observers.  Cooler weather will bring several flights of these spectacular species.  Why not plan a visit to a lookout near you?  Click on the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab at the top of this page for site information and a photo guide to identification.  See you at the hawk watch!

Common Raven
It’s not all hawks at the hawk watch.  Even the coastal sites are now seeing fun birds like the playful Common Raven on a regular basis.
Eastern Meadowlarks in a Loblolly Pine.
Coastal locations are renowned places to see migrating songbirds in places outside of their typical habitat.  Here a flock of Eastern Meadowlarks has set down in the top of a Loblolly Pine (Pinus taeda) in downtown Cape Charles, Virginia, not far from Kiptopeke Hawk Watch.

Plantings for Wet Lowlands

This linear grove of mature trees, many of them nearly one hundred years old, is a planting of native White Oaks (Quercus alba) and Swamp White Oaks (Quercus bicolor).

Imagine the benefit of trees like this along that section of stream you’re mowing or grazing right now.  The Swamp White Oak in particular thrives in wet soils and is available now for just a couple of bucks per tree from several of the lower Susquehanna’s County Conservation District Tree Sales.  These and other trees and shrubs planted along creeks and rivers to create a riparian buffer help reduce sediment and nutrient pollution.  In addition, these vegetated borders protect against soil erosion, they provide shade to otherwise sun-scorched waters, and they provide essential wildlife habitat.  What’s not to love?

Swamp White Oak
Autumn leaf of a Swamp White Oak

The following native species make great companions for Swamp White Oaks in a lowland setting and are available at bargain prices from one or more of the County Conservation District Tree Sales now underway…

Red Maple
The Red Maple is an ideal tree for a stream buffer project. They do so well that you should limit them to 10% or less of the plants in your project so that they don’t overwhelm slower-growing species.
River Birch
The River Birch (Betula nigra) is a multi-trunked tree of lowlands.  Large specimens with arching trunks help shade waterways and provide a source of falling insects for surface-feeding fish.  Its peeling bark is a distinctive feature.
Common Winterberry
The Common Winterberry with its showy red winter-time fruit is a slow-growing shrub of wet soils.  Only female specimens of this deciduous holly produce berries, so you need to plant a bunch to make sure you have both genders for successful pollination.
American Robins feeding on Common Winterberry.
An American Robin feeding on Common Winterberry.
Common Spicebush
Common Spicebush is a shrub of moist lowland soils.  It is the host plant for the Spicebush Swallowtail butterfly and produces small red berries for birds and other wildlife.  Plant it widely among taller trees to provide native vegetation in the understory of your forest.
Common Spicebush foliage and berries.
Common Spicebush foliage and berries in the shade beneath a canopy of tall trees.
Common Pawpaw
The Common Pawpaw a small shade-loving tree of the forest understory.
Common Pawpaw
Common Pawpaw is a colony-forming small tree which produces a fleshy fruit.  It is the host plant for the caterpillars of the Zebra Swallowtail.
Buttonbush
The Buttonbush is a shrub of wet soils.  It produces a round flower cluster, followed by this globular seed cluster.
Eastern Sycamore
And don’t forget the Eastern Sycamore, the giant of the lowlands.  At maturity, the white-and-tan-colored bark on massive specimens makes them a spectacular sight along stream courses and river shores.  Birds ranging from owls, eagles, and herons to smaller species including the Yellow-throated Warbler rely upon them for nesting sites.
Yellow-crowned Night Herons Nesting in an Eastern Sycamore
Yellow-crowned Night Herons, an endangered species in Pennsylvania, nesting in an Eastern Sycamore.

So don’t mow, do something positive and plant a buffer!

Act now to order your plants because deadlines are approaching fast.  For links to the County Conservation District Tree Sales in the Lower Susquehanna River Watershed, see our February 18th post.

Photo of the Day

Soaring Bald Eagle
It’s time to keep an eye on the sky when you’re out and about.  Not only are mated pairs of Bald Eagles beginning their nesting cycle throughout the Lower Susquehanna River Watershed, but migrating birds are passing through the area on their way to breeding grounds farther north. This one drew the ire of pairs of Fish Crows and American Crows as it soared above the susquehannawildlife.net headquarters earlier today.

Are Your Eggs All They’re Cracked Up To Be?

Looks like I’m gonna be in the doghouse again—this time by way of the hen house.  But why should I care?  Here we go.

A few weeks ago, back when eggs were still selling for less than five dollars a dozen, the Pennsylvania Department of Agriculture renewed calls for owners and caretakers of outdoor flocks of domestic poultry (backyard chickens) to keep their birds indoors to protect them from the spread of  bird flu—specifically “Highly Pathogenic Avian Influenza” (H.P.A.I.).  At least one story edited and broadcast by a Susquehanna valley news outlet gave the impression that “vultures and hawks” are responsible for the spread of avian flu in chickens.  To see if recent history supports such a deduction, let’s have a look at the U.S.D.A.’s Animal and Plant Health Inspection Service’s 2022-2023 list of the  detection of Highly Pathogenic Avian Influenza in birds affected in counties of the Lower Susquehanna River Watershed in Pennsylvania.

H.P.A.I. 2022 Confirmed Detections as of January 13, 2023

This listing includes date of detection, county of collection, type/species of bird, and number of birds affected.  WOAH (World Organization for Animal Health) birds include backyard poultry, game birds raised for eventual release, domestic pet species, etc.

12/30/2022  Adams            Black Vulture

12/15/2022   Lancaster     Canada Goose

12/15/2022   Lebanon        Black Vulture

12/15/2022   Adams            Black Vulture (3)

11/8/2022     Cumberland Black Vulture (4)

11/4/2022      Dauphin         WOAH Non-Poultry (130)

10/19/2022   Dauphin         Captive Wild Rhea (4)

10/17/2022   Adams            Commercial Turkey (15,100)

10/11/2022    Adams            WOAH Poultry (2,800)

9/30/2022    Lancaster      Mallard

9/30/2022    Lancaster      Mallard

9/29/2022     Lancaster     WOAH Non-Poultry (180)

9/29/2022     York                 Commercial Turkey (25,900)

8/24/2022     Dauphin         Captive Wild Crane

7/15/2022      Lancaster     Great Horned Owl

7/15/2022      York                 Bald Eagle

7/15/2022      Dauphin         Bald Eagle

6/16/2022      Dauphin         Black Vulture

6/16/2022      Dauphin         Black Vulture (4)

5/31/2022      Lancaster      Black Vulture (2)

5/31/2022      Lancaster      Black Vulture

5/10/2022-Lncstr-Commercial Egg Layer (72,300)

4/29/2022-Lncstr-Commercial Duck (19,300)

4/27/2022-Lncstr-Commercial Broiler (18,100)

4/26/2022-Lncstr-Commercial Egg Layer (307,400)

4/22/2022-Lncstr-Commercial Broiler (50,300)

4/20/2022-Lncstr-Commercial Egg Layer (1,127,700)

4/20/2022-Lncstr-Commercial Egg Layer (879,400)

4/15/2022-Lncstr-Commercial Egg Layer (1,380,500)

In the Lower Susquehanna River Watershed, it’s pretty obvious that the outbreak of avian flu got its foothold inside some of the area’s big commercial poultry houses.  Common sense tells us that hawks, vultures, and other birds didn’t migrate north into the Lower Susquehanna River Watershed carrying bird flu, then kick in the doors of the enclosed hen houses to infect the flocks of chickens therein.   Anyone paying attention during these past three years knows that isolation and quarantine are practices more easily proposed than sustained.  Human footprints are all over the introduction of this infection into these enormous flocks.  Simply put, men don’t wipe their feet when no one is watching!  The outbreak of bird flu in these large operations was brought under control quickly, but not until teams of state and federal experts arrived to assure proper sanitary and isolation practices were being implemented and used religiously to prevent contaminated equipment, clothing, vehicles, feed deliveries, and feet from transporting virus to unaffected facilities.  Large poultry houses aren’t ideal enclosures with absolute capabilities for excluding or containing viruses and other pathogens.  Exhaust systems often blow feathers and waste particulates into the air surrounding these sites and present the opportunity for flu to be transported by wind or service vehicles and other conveyances that pass through contaminated ground then move on to other sites—both commercial and non-commercial.  Waste material and birds (both dead and alive) removed from commercial poultry buildings can spread contamination during transport and after deposition.  The sheer volume of the potentially infected organic material involved in these large poultry operations makes absolute containment of an outbreak nearly impossible.

A farm with a biosecurity perimeter or control area.  (United States Department of Agriculture Animal and Plant Inspection Service image)
A U.S.D.A. Animal and Plant Inspection Service Veterinary Services employee decontaminates footwear at the entrance to a biosecurity zone.  (United States Department of Agriculture Animal and Plant Inspection Service image)

Looking at the timeline created by the list of U.S.D.A. detections, the opportunity for bird flu to leave the commercial poultry loop probably happened when wild birds gained access to stored or disposed waste and dead animals from an infected commercial poultry operation.  For decades now, many poultry operations have dumped dead birds outside their buildings where they are consumed by carrion-eating mammals, crows, vultures, Bald Eagles, and Red-tailed Hawks.  For these species, discarded livestock is one of the few remaining food sources in portions of the Lower Susquehanna River Watershed where high-intensity farming has eliminated other forms of sustenance.  They will travel many miles and gather in unnatural concentrations to feast on these handouts—creating ideal circumstances for the spread of disease.

The sequence of events indicated by the U.S.D.A. list would lead us to infer that vultures and Bald Eagles were quick to find and consume dead birds infected with H5N1—either wild species such as waterfowl or more likely domestic poultry from commercial operations or from infectious backyard flocks that went undetected.  As the report shows, Black Vultures in particular seem to be susceptible to morbidity.  Their frequent occurrence as victims highlights the need to dispose of potentially infectious poultry carcasses properly—allowing no access for hungry wildlife including scavengers.

Black Vultures
Black Vultures and other scavengers including Bald Eagles are attracted to improperly discarded poultry carcasses and will often loiter in areas where dumping occurs.

The positive test on a Great Horned Owl is an interesting case.  While the owl may have consumed an infected wild bird such as a crow, there is the possibility that it consumed or contacted a mammalian scavenger that was carrying the virus.  Aside from rodents and other small mammals, Great Horned Owls also prey upon Striped Skunks with some regularity.  Most of the dead poultry from flu-infected commercial flocks was buried onsite in rows of above-ground mounds.  Skunks sniff the ground for subterranean fare, digging up invertebrates and other food.  Buried chickens at a flu disposal site would constitute a feast for these opportunistic foragers.  A skunk would have no trouble at all finding at least a few edible scraps at such a site.  Then a Great Horned Owl could easily seize and feed upon such a flu virus-contaminated skunk.

Striped Skunk
Striped Skunks and many other mammals are readily attracted by improperly discarded poultry carcasses.

BACKYARD POULTRY

Before we proceed, the reader must understand the seldom-stated and never advertised mission of the Pennsylvania Department of Agriculture—to protect the state’s agriculture industry.  That’s it; that’s the bottom line.  Regulation and enforcement of matters under the purview of the agency have their roots in this goal.  While they may also protect the public health, animal health, and other niceties, the underlying purpose of their existence in its current manifestation is to protect the agriculture industry(s) as a whole.

This is not a trait unique to the Pennsylvania Department of Agriculture.  It is at the core of many other federal and state agencies as well.  Following the publication of Upton Sinclair’s The Jungle in 1906, a novel decrying “wage slavery” in the meat packing industry, the federal government took action, not for the purpose of improving the working conditions for labor, but to address the unsanitary food-handling practices described in the book by creating an inspection program to restore consumer confidence in the commercially-processed meat supply so that the industry would not crumble.

Locally, few things make the dairy industry and the Pennsylvania Department of Agriculture more nervous than small producers selling “raw milk”.  In the days before pasteurization and refrigeration, people were frequently sickened and some even died from drinking bacteria-contaminated “raw milk”.  In Pennsylvania, the production and sale of dairy products including “raw milk” is closely regulated and requires a permit.  Retention of a permit requires submitting to inspections and passing periodic herd and product testing.  Despite the dangers, many consumers continue to buy “raw milk” from farms without permits.  These sales are like a ticking time bomb.  The bad publicity from an outbreak of food-borne illness traced back to a dairy product—even if it originated in an “outlaw” operation—could decimate sales throughout the industry.  Because just one sloppy farm selling “raw milk” could instantly erode consumer confidence and cause an industry-wide collapse of the market resulting in a loss of millions of dollars in sales, it is a deeply concerning issue.

Enter the backyard chicken—a two-fold source of anxiety for the poultry industry and its regulators.  Like unregulated meat and dairy products, eggs and meat from backyard poultry flocks are often marketed without being monitored for the pathogens responsible for the transmission of food-borne illness.  From the viewpoint of the poultry industry, this situation poses a human health risk that in the event of an outbreak, could erode consumer confidence, not only in homegrown organic and free-range products, but in the commercial line of products as well.  Consumers can be very reactive upon hearing news of an outbreak, recalling few details other than “the fowl is foul”— then refraining from buying poultry products.  The second and currently most concerning source of trepidation among members of the poultry industry though is the threat of avian flu and other diseases being harbored in and transmitted via flocks of backyard birds.

The Green Revolution, the post-World War II initiative that integrated technology into agriculture to increase yields and assure an adequate food supply for the growing global population, brought changes to the way farmers raised poultry for market.  Small-scale poultry husbandry slowly disappeared from many farms.  Instead, commercial operations concentrated birds into progressively-larger indoor flocks to provide economy of scale.  Over time, genetics and nutrition science have provided the American consumer with a line of readily available high-quality poultry products at an inexpensive price.  Within these large-scale operations, poultry health is closely monitored.  Though these enclosures may house hundreds of thousands of birds, the strategy during an outbreak of communicable disease is to contain an outbreak to the flock therein, writing it off so to speak to prevent the pathogens from finding their way into the remainder of the population in a geographic area, thus saving the industry at the expense of the contents of a single operation.  Adherence to effective biosecurity practices can contain outbreaks in this way.

An offshoot of the Green Revolution, a large-scale poultry operation.
Modern science has produced a genetic map of the domestic chicken (Gallus gallus domesticus) allowing faster development of varieties with improved disease resistance, productivity, and other traits.  (United States Department of Agriculture image by Peggy Greb)
A technician checks eggs produced by immunized birds for the presence of flu virus.  A flu vaccine could provide an added layer of protection to biosecurity in the poultry industry.  (United States Department of Agriculture image by Stephen Ausmus)

The renewed popularity of backyard poultry is a reversal of the decades-long trend towards reliance on ever-larger indoor operations for the production of birds and eggs.  But backyard flocks may make less-than-ideal neighbors for commercial operations, particularly when birds are left to roam outdoors.  Visitors to properties with roaming chickens, ducks, geese, and turkeys may pick up contamination on their shoes, clothing, tires, and equipment, then transmit the pathogenic material to flocks at other sites they visit without ever knowing it.  Even the letter carrier can carry virus from a mud puddle on an infected farm to a grazing area on a previously unaffected one.  Unlike commercial operations, hobby farms frequently buy, sell, and trade livestock and eggs without regard to disease transmission.  The rate of infection in these operations is always something of a mystery.  No state or county permits are required for keeping small numbers of poultry and outbreaks like avian flu are seldom reported by caretakers of flocks of home-raised birds, though their occurrence among them may be widespread.  The potential for pathogens like avian flu virus circulating long-term among flocks of backyard poultry in close proximity to commercial houses is a real threat to the industry.

Live poultry and eggs are frequently sold to and traded among operators of backyard flocks without monitoring for disease.  (United States Department of Agriculture image by Keith Weller.)

There are a variety of motivations for tending backyard poultry.  While for some it is merely a form of pet keeping, others are more serious about the practice—raising and breeding exotic varieties for show and trade.  Increasingly, backyard flocks are being established by people seeking to provide their own source of eggs or meat.  For those with larger home operations,  supplemental income is derived from selling their surplus poultry products.  Many of these backyard enthusiasts are part of a movement founded on the belief that, in comparison to commercially reared birds, their poultry is raised under healthier and more humane conditions by roaming outdoors.  Organic operators believe their eggs and meat are safer for consumption—produced without the use of chemicals.  For the movement’s most dedicated “true believers”, the big poultry industry is the antagonist and homegrown fowl is the only hope.  It’s similar to the perspective members of the “raw milk” movement have toward pasteurized milk.  True believers are often willing to risk their health and well-being for the sake of the cause, so questioning the validity of their movement can render a skeptic persona non grata.

What’s in your eggs?  (United States Department of Agriculture image by Peggy Greb)

For the consumer, the question arises, “Are eggs and poultry from the small-scale operations better?”

While many health-conscious animal-friendly consumers would agree to support the small producer from the local farm ahead of big business, the reality of supplying food for the masses requires the economy of scale.  The billions of people in the world can’t be fed using small-scale and/or organic growing methods.  The Green Revolution has provided record-high yields by incorporating herbicides, insecticides, plastic, and genetic modification into agriculture.  To protect livestock and improve productivity, enormous indoor operations are increasingly common.  Current economics tell the story—organic production can’t keep up with demand, that’s why the prices for items labelled organic are so much higher.

A commercial poultry operation (in this case turkeys) produces economical consumer products.  (United States Department of Agriculture image by Scott Bauer)

To the consumer, buying poultry raised outdoors is an appealing option.  Compared to livestock crowded into buildings, they feel good about choosing products from small operations where birds roam free and happy in the sunshine.

An outdoor flock of backyard chickens.  (United States Department of Agriculture Animal and Plant Inspection Service image)

But is the quality really better?  Some research indicates not.  Salmonella outbreaks have been traced back to poultry meat sourced from small unregulated operations.  Studies have found dioxins in eggs produced by hens left to forage outdoors.  The common practice of burning trash can generate a quantity of ash sufficient to contaminate soils with dioxins, chemical compounds which persist in the environment and in the fatty tissue of animals for years.  The presence of elevated levels of dioxins in eggs from outdoor grazing operations may pose a potential consumer confidence liability for the entire egg industry.

Birds raised or kept in an outdoor zoo or backyard poultry setting can be susceptible to viruses and other pathogens when wild birds including vultures and hawks become attracted to the captives’ food and water when it is placed in an accessible location.  In addition, hunting and scavenging birds are opportunistic— attracted to potential food animals when they perceive vulnerability.  Selective breeding under domestication has rendered food poultry fat, dumb, and too genetically impaired for survival in the wild.  These weaknesses instantly arouse the curiosity of raptors and other predators whose function in the food web is to maintain a healthy population of animals at lower tiers of the food chain by selectively consuming the sickly and weak.  In settings such as those created by high-intensity agriculture and urbanization, wild birds may find the potential food sources offered by outdoor zoos and backyard poultry irresistible.  As a result they may perch, loaf, and linger around these locations—potentially exposing the captive birds to their droppings and transmission of bird flu and other diseases.

Variation produced under domestication has left poultry unfit for life among the perils found outdoors.  (United States Department of Agriculture image)
Turkey Vulture and White-tailed Deer
Millions of years of natural selection have made scavengers and predators ideally suited for the role of detecting and consuming dead, dying, and diseased wild animals, thus reducing accumulations of rotting carcasses and the spread of infectious pathogens among prey species.  Their distribution and reproductive success is closely controlled by the availability of food.  Humans need not disturb this balance or create unnatural congregations of these animals by providing supplemental foods such as dead poultry.

While outdoor poultry operations usually raise far fewer birds than their commercial counterparts, their animals are still kept in densities high enough to promote the rapid spread of microbiological diseases.  Clusters of outdoor flocks can become a reservoir of pathogens with the capability of repeatedly circulating disease into populations of wild birds and even into commercial poultry operations—threatening the industry and food supply for millions of people.  For this reason, state and federal agencies are encouraging operators to keep backyard poultry indoors—segregated from natural and anthropogenic disease vectors and conveyances that might otherwise visit and interact with the flock.

BACK TO THE FUTURE?—NOT LIKELY

The hobby farmer, the homesteader, the pet keeper, and the consumer seldom realize what the modern farmer is coming to know—domestic livestock must be segregated from the sources of contamination and disease that occur outdoors.  Adherence to this simple concept helps assure improved health for the animals and a safer food supply for consumers.  In the future, outdoor production of domestic animals, particularly those used as a food supply, is likely to be classified as an outdated and antiquated form of animal husbandry.

Outside and Inside Animals
It’s as simple as ABC and 123.
Cage-free chickens can be housed within the protective envelop of a building where they can be segregated from the microbes and pollutants found outdoors.  The U.S.D.A. defines “free-range” poultry as birds with some access to an outdoor setting where the benefits of biosecurity and quarantine are, for all intents and purposes, nullified.  (United States Department of Agriculture image by Stephen Ausmus)
Pigs
Pigs raised outdoors by homesteaders and hobby farmers pose the threat of spreading a number of diseases including Swine Fevers and Brucellosis into pork industry operations.   Escaped individuals are often attracted to commercial hog houses where they can loiter outside and contaminate the ground surrounding entrance ways used by personnel tending the animals.  Like other domestic animals, pigs should be contained inside buildings for biosecurity.
Dairy cows in an indoor feed lot.
Dairy cows and other cattle raised within well-designed indoor and semi-indoor settings are less prone to injury and consumption of contaminated foods and water.
Domestic Cat
Domestic Cats (Felis catus), particularly when allowed to roam outdoors, can contract the parasite Toxoplasma gondii during interactions with mice.  Humans, dogs, pigs, and other animals coming in contact with the Toxoplasma oocysts shed in feline feces can contract Toxoplasmosis, a disease with various physical and mental health symptoms.  According to the Centers for Disease Control, there are approximately three million cases of Toxoplasmosis among humans in the United States annually.

THE THREAT FROM PRIONS

If there are three things the world learned from the SARS CoV-2 (Covid-19) epidemic, it’s that 1) eating or handling bush meat can bring unwanted surprises, 2) dense populations of very mobile humans are ideal mediums for uncontrolled transmission of disease, and 3) quarantine is easier said than done.

If you think viruses are bad, you don’t even want to know about prions.  Prions are a prime example of why now is a good time to begin housing domestic animals, including pets, indoors to segregate them from wildlife.  And prions are a good example of why we really ought to think twice about relying on wild animals as a source of food.  Prions may make us completely rethink the way we interact with animals of any kind—but we had better do our thinking fast because prions turn the brains of their victims into Swiss cheese.

Stained slide of cow brain tissue affected by Bovine Spongiform Encephalopathy (BSE). The pale-colored air pockets are voids in the tissue caused by the disease.  (United States Department of Agriculture image by the late Dr. Al Jenny)

Diseases caused by prions are rapidly progressing neurodegenerative disorders for which there is no cure.  Prions are an abnormal isoform of a cellular glycoprotein.  They are currently rare, but prions, because they are not living entities, possess the ability to begin accumulating in the environment.  They not only remain in detritus left behind by the decaying carcasses of afflicted animals, but can also be shed in manure—entering soils and becoming more and more prevalent over time.  Some are speculating that they could wind up being man’s downfall.

The  Centers for Disease Control lists these human afflictions caused by prions…

The Centers for Disease Control lists these prion-caused ailments of other animals…

Dairy cows in a pasture.
Bovine Spongiform Encephalopathy (BSE), also known as Mad Cow Disease, is a neurodegenerative disorder fatal to cattle.  It is caused by the same prion that, when consumed or otherwise contracted by humans, causes Creutzfekd-Jokob Disease (CJD).
Chronic Wasting Disease (CWD), a fatal disease caused by a prion, is currently spreading among populations of the White-tailed Deity in the mid-Atlantic region.  Prions are understood to be folded proteins, not living things, thus they are not destroyed by cooking and other disinfection practices.  If you are wondering whether various forms of these pathogens will begin accumulating in the environment and affecting more and more species with new and more frightening afflictions, well, time will tell.  Meanwhile, we at susquehannawildlife.net are staying away from “game” and any other form of bush meat.  Thanks, but no thanks!
The future with a safe food supply will require domestic animals to be contained indoors while wildlife roams unmolested outdoors.

SOURCES

Schoeters, Greet, and Ron Hoogenboom.  2006.  Contamination of Free-range Chicken Eggs with Dioxins and Dioxin-like Polychlorinated Biphenyls.  Molecular Nutrition and Food Research.  (10):908-14.

Szczepan, Mikolajczyk, Marek Pajurek, Malgorzata Warenik-Bany, and Sebastian Maszewski.  2021.  Environmental Contamination of Free-range Hen with Dioxin.  Journal of Veterinary Research.  65(2):225-229.

U.S.D.A. Animal and Plant Inspection Service.  2022 Confirmations of Highly Pathogenic Avian Influenza.  aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022/2022-hpai-commercial-backyard-flocks as accessed January 14, 2023.

U.S.D.A. Animal and Plant Inspection Service.  2022 Confirmations of Highly Pathogenic Avian Influenza.  aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022/2022-hpai-wild-birds  as accessed January 14, 2023.

Northwest Winds in November Bring Big Birds

With colder temperatures arriving on gusty northwest winds, the next couple of days will be ideal for seeing migrating birds of prey along the ridges of the Lower Susquehanna River Watershed.  It’s still peak time for movements of four of our largest species: Red-shouldered Hawk, Red-tailed Hawk, Bald Eagle, and Golden Eagle—so let’s grab our binoculars and have a look!

A juvenile Red-shouldered Hawk gliding past a ridgetop hawk counting station.
A juvenile Red-shouldered Hawk gliding past a ridgetop hawk-counting station.
A juvenile Red-tailed Hawk headed south for winter.
A juvenile Red-tailed Hawk headed south for winter.
A juvenile Bald Eagle.
A juvenile Bald Eagle is an attention-getter.
 Golden Eagle
The regal Golden Eagle always creates excitement among observers at regional hawk watches.

Be certain to click the “Hawkwatcher’s Helper” tab at the top of this page to select a lookout for observing and enjoying the passage of these spectacular late-season raptors.  To improve your chances of seeing a Golden Eagle, visit a counting station in the Ridge and Valley Province, but do bundle up—it’s cold on those mountaintops.

Big Broad-winged Hawk Flights Are Underway

Flights of southbound Broad-winged Hawks have joined those of other Neotropical migrants to thrill observers with spectacular numbers.  In recent days, thousands have been seen and counted at many of the regions hawkwatching stations.  Now is the time to check it out!

A "kettle" of Broad-winged Hawks gaining altitude by soaring on a thermal updraft.
A “kettle” of Broad-winged Hawks gaining altitude by soaring on a thermal updraft.
Migrating Broad-winged Hawks
Broad-winged Hawks gliding away to the southwest after climbing in a column of rising warm air.
Broad-winged Hawk
A migrating Broad-winged Hawk enroute to the tropics for winter.

Other diurnal migrants are on the move as well…

Migratory Woodpeckers: Red-bellied Woodpecker and Northern Flicker
The Red-bellied Woodpecker (left) and the Northern Flicker (right) are migratory species of woodpeckers that begin heading south during the last half of September each year.
Migrating Blue Jay
Running a bit early, large numbers of Blue Jays having been moving through the area for several weeks now.
Flock of Cedar Waxwings
Flocks of Cedar Waxwings roam widely as they creep ever southward for winter.

Adding to the diversity of sightings, there are these diurnal raptors arriving in the area right now…

Juvenile Sharp-shinned Hawk
Numbers of migrating Sharp-shinned Hawks are building and will peak during the coming weeks.
Juvenile Cooper's Hawk
As will numbers of Cooper’s Hawks.
Merlin
The Merlin and other falcons peak in late September and early October.
Adult Bald Eagle
And Bald Eagles are moving throughout the fall season.

For more information and directions to places where you can observe migrating hawks and other birds, be certain to click the “Hawkwatcher’s Helper” tab at the top of this page.

The Blizzard Has Arrived: Snow Geese at Middle Creek

It’s that time of year—Snow Geese on their northbound migration, more than 100,000 of them, have arrived for a stopover at the Pennsylvania Game Commission’s Middle Creek Wildlife Management Area in Lancaster and Lebanon Counties.  Get there now to see scenes like these in person…

Snow Geese at Middle Creek Wildlife Management Area
Thousands of Snow Geese gather on the main impoundment at Middle Creek.  Presently, over 100,000 are estimated to be visiting the refuge.
Tundra Swans at Middle Creek Wildlife Management Area
More than two thousand Tundra Swans are visiting Middle Creek right now too.
female American Kestrel
A passing American Kestrel doesn’t seem to ruffle any feathers among the multitudes of Snow Geese on the lake…
Bald Eagles at Middle Creek Wildlife Management Area
…but when the local pair of Bald Eagles gets close, such as when they’re escorting a third party away from their nesting territory, …
Snow Geese at Middle Creek Wildlife Management Area
…Snow Geese lift off in a panic.
Snow Geese at Middle Creek Wildlife Management Area
Snow Geese rise above the shoreline treetops.
Snow Geese at Middle Creek Wildlife Management Area
Feeding and roosting Snow Geese take flight in the presence of a potential predator to not only make a direct escape, but also to seek a safer position toward the center of the flock, keeping away from the vulnerable areas on the periphery.
Snow Geese and Tundra Swans at Middle Creek Wildlife Management Area
Thousands of Snow Geese rise behind the placid group of Tundra Swans in the foreground.
Snow Geese at Middle Creek Wildlife Management Area
Observers along Willow Point Trail with swarming Snow Geese just ahead.
Snow Geese at Middle Creek Wildlife Management Area
In the midst of the thunderous cackle of thousands of Snow Geese.
Snow Geese at Middle Creek Wildlife Management Area
Don’t forget your camera…
Snow Geese at Middle Creek Wildlife Management Area
…for an unforgettable photo op at Willow Point.

Hey, Let’s Go to Conowingo: It’s Bald Eagle Time

Why are there dozens of people with enormous lenses on complicated cameras atop sturdy tripods gathered at Fisherman’s Park below the Conowingo Dam on the lower Susquehanna River in Maryland?  It’s Bald Eagle time, that’s why.  Here are some photos from the scene, taken just two days ago.

Dozens of observers and photographers line up along the Harford County shoreline of the Susquehanna downstream of the powerhouse at the Conowingo Hydroelectric Station, the majority awaiting the opportunity to catch a shot of a Bald Eagle grabbing a fish from the river just in front of them.  Visitors travel to Conowingo from all over the continental United States to see and photograph eagles in concentrations that are often rivaled only in less accessible areas of Alaska and Canada.
Bald Eagles migrate to the lower Susquehanna near Conowingo and the upper Chesapeake Bay to spend the early winter in congregations that can, in good years, number in the hundreds of birds. There are presently at least 60 to 80 Bald Eagles present, and numbers are increasing.
If you visit, you’ll have a chance to see Bald Eagles in the various stages of plumage transition experienced during the six years needed to acquire the familiar all-white head and tail of adulthood.  This particular immature eagle is in its third year.  Birds at this age are sometimes known as “Osprey face” Bald Eagles due to the dark stripe through the eye.  Be certain to click the “Hawkwatchers Helper: Identifying Bald Eagles and other Diurnal Raptors” tab at the top of this page to see a photographic guide to aging the eagles and other birds of prey you observe.
An adult Bald Eagle snags a fish from the Susquehanna in front of photographers and gets the cameras clicking and other eagles in the area cackling and chattering.
The majority of the Bald Eagles at Conowingo are there for the early winter only; they’ll disperse to their nesting grounds later in the season.  An exception is this mated pair that is already at their nest site adjacent to the Fisherman’s Park car lot.  They can often be seen perched in the treetops directly above visitor’s vehicles.

To reach Exelon Energy’s Conowingo Fisherman’s Park from Rising Sun, Maryland, follow U.S. Route 1 south across the Conowingo Dam, then turn left onto Shuresville Road, then make a sharp left onto Shureslanding Road.  Drive down the hill to the parking area along the river.  The park’s address is 2569 Shureslanding Road, Darlington, Maryland.

Do make an excursion to the lower Susquehanna at Conowingo soon.  To avoid crowds and parking congestion, plan to visit on a weekday.  You’ll want warm clothing, binoculars, and a camera too.

The Fisherman’s Park Bald Eagles copulating.  If you don’t know what that is, ask your mother…no, wait, on second thought, look it up on the internet.

A Visit to Bombay Hook National Wildlife Refuge

It’s surprising how many millions of people travel the busy coastal routes of Delaware each year to leave the traffic congestion and hectic life of the northeast corridor behind to visit congested hectic shore towns like Rehobeth Beach, Bethany Beach, and Ocean City, Maryland.  They call it a vacation, or a holiday, or a weekend, and it’s exhausting.  What’s amazing is how many of them drive right by a breathtaking national treasure located along Delaware Bay just east of the city of Dover—and never know it.  A short detour on your route will take you there.  It’s Bombay Hook National Wildlife Refuge, a quiet but spectacular place that draws few crowds of tourists, but lots of birds and other wildlife.

Bombay Hook National Wildlife Refuge is located just off Route 9, a lightly-traveled coastal road east of Dover, Delaware.  Note the Big Bluestem and other warm season grasses in the background.  Bombay Hook, like other refuges in the system, is managed for the benefit of the wildlife that relies upon it to survive.  Within recent years, most of the mowed grass and tilled ground that once occurred here has been replaced by prairie grasses or successional growth, much to the delight of Northern Bobwhite (Colinus virginianus) and other species.

Let’s join Uncle Tyler Dyer and have a look around Bombay Hook.  He’s got his duck stamp and he’s ready to go.

Uncle Ty’s current United States Fish and Wildlife Service Duck Stamp displayed on his dashboard is free admission to the tour road at Bombay Hook and other National Wildlife Refuges.
The refuge at Bombay Hook includes woodlands, grasslands, and man-made freshwater pools, but it is predominately a protectorate of thousands of acres of tidal salt marsh bordering and purifying the waters of Delaware Bay.  These marshes are renowned wintering areas for an Atlantic population of Snow Goose known as the “Greater Snow Goose” (Anser caerulescens atlanticus).  Witnessing thousands of these birds rising over the marsh and glowing in the amber light of a setting sun is an unforgettable experience.
Trails at various stops along the auto tour route lead to observation towers and other features. This boardwalk meanders into the salt marsh grasses and includes a viewing area alongside a tidal creek.  Our visit coincided with a very high tide induced by east winds and a new moon.
During high tide, an Eastern Cottontail (Sylvilagus floridanus) seeks higher ground near the boardwalk and the wooded edge of the salt marsh.
As the tide rises, fast-flying shorebirds scramble from flooded mudflats in the salt marsh on the east side of the tour road.
When high tide arrives in the salt marshes, shorebirds and waterfowl often concentrate in the man-made freshwater pools on the west side of the tour road.  Glaring afternoon sun is not the best for viewing birds located west of the road.  For ideal light conditions, time your visit for a day when high tide occurs in the morning and recedes to low tide in the afternoon.
A view looking west into Shearness Pool, largest of the freshwater impoundments at Bombay Hook.
Bombay Hook has many secretive birds hiding in its wetlands, but they can often be located by the patient observer.  Here, two Pied-billed Grebes feed in an opening among the vegetation in a freshwater pool.
One of Bombay Hook’s resident Bald Eagles patrols the wetlands.
American Avocets (Recurvirostra americana) gather by the hundreds at Bombay Hook during the fall.  A passing eagle will stir them into flight.
An American Avocet, a delicate wader with a peculiar upturned bill.
As soon as the tide begins receding, shorebirds and waterfowl like these Green-winged Teal begin dispersing into the salt marshes to feed on the exposed mudflats.
The woodlands and forested areas of the refuge host resident songbirds and can be attractive to migrating species like this Yellow-rumped Warbler.
For much of its course, the tour road at Bombay Hook is located atop the dike that creates the man-made freshwater pools on the western edge of the tidal salt marsh.  If you drive slowly and make frequent stops to look and listen, you’ll notice an abundance of birds and other wildlife living along this border between two habitats.  Here, a Swamp Sparrow has a look around.
Savannah Sparrows are common along the tour road where native grasses grow wild.
Bombay Hook is renowned for its rarities. One of the attractions during the late summer and autumn of 2021 was a group of Roseate Spoonbills (Platalea ajaja), vagrants from the southern states, seen here with Great Egrets and Snowy Egrets (Egretta thula).
Roseate Spoonbills and Great Egrets at Bombay Hook.

Remember to go the Post Office and get your duck stamp.  You’ll be supporting habitat acquisition and improvements for the wildlife we cherish.  And if you get the chance, visit a National Wildlife Refuge.  November can be a great time to go, it’s bug-free!  Just take along your warmest clothing and plan to spend the day.  You won’t regret it.

Migration Update

Can it be that time already?  Most Neotropical birds have passed through the Lower Susquehanna River Watershed on their way south and the hardier species that will spend our winter in the more temperate climes of the eastern United States are beginning to arrive.

Here’s a gallery of sightings from recent days…

During the past two weeks, thousands of Broad-winged Hawks, including this adult bird, crossed the skies of the lower Susquehanna valley on their way to Central and South America for our winter.
A juvenile Broad-winged Hawk passes into the sunset during its first autumn migration.
Blackpoll Warblers are among the last of the Neotropical species to transit the region.  They’ll continue to be seen locally through at least early October.
Blue-headed Vireos are the October vireo during the fall, the other species having already continued toward tropical forests for a winter vacation.
The lower Susquehanna region lies just on the northern edge of the wintering range of the Blue-gray Gnatcatcher, a species found nesting locally among treetops in deciduous woods.  Look for their numbers to swell in coming days as birds from further north begin rolling through the region on their way south.
Sharp-shinned Hawks delight visitors at ridgetop hawk watches during breezy late-September and early-October days.  They allow closer observation than high-flying Broad-winged Hawks due to their habit of cruising just above the treetops while migrating.
A Sharp-shinned Hawk glides over a lookout.
Late September/early October is falcon time at area hawk-counting stations, the Peregrine Falcon often being the most anticipated species.
Pale “Tundra Peregrines”, a subspecies that nests in the arctic, are strictly migratory birds in the Mid-Atlantic States.  They are presently passing through on their way to South America.  Like Neotropical songbirds, their long flights provide them with the luxury of never experiencing a winter season.
This Carolina Saddlebags and other migratory dragonflies, which normally leave the area by mid-September, are still lingering in the lower Susquehanna region, much to the pleasure of the falcons that feed upon them.
An male American Kestrel in pursuit of dragonflies found swarming around the lookout at Second Mountain Hawk Watch in Lebanon County, Pennsylvania.
A male American Kestrel stooping on a dragonfly.
Osprey will be among the birds of prey passing hawk watch sites during the coming two weeks.  The first week of October often provides the best opportunity for seeing the maximum variety of raptors at a given site.  On a good day, a dozen species are possible.
Seeing cinnamon-colored juvenile Northern Harriers is symbolic of the October migration flights.
Bald Eagles always thrill the crowd.
In addition to raptors, resident Common Ravens are regularly sighted by observers at hawk watches and elsewhere during the fall season.
Hawk-counting stations sometimes log movements of Red-bellied Woodpeckers during late September and early October.  This species has extended its range into the Lower Susquehanna River Watershed only during the past one hundred years, making these seasonal migration movements a recent local phenomenon.
Blue Jays are currently on the move with breeding birds from the forests of Canada and the northern United States moving south.  Hundreds can be seen passing a given observation point during an ideal morning.
Blue Jays find a pile of peanuts to be an irresistible treat.  Provide the unsalted variety and watch the show!

Be sure to click on these tabs at the top of this page to find image guides to help you identify the dragonflies, birds, and raptors you see in the Lower Susquehanna River Watershed…

    • Damselflies and Dragonflies
    • Birds of Conewago Falls
    • Hawkwatcher’s Helper: Identifying Bald Eagles and other Raptors

See you next time!

Smoky Skies in the Lower Susquehanna Region

During the coming two weeks, peak numbers of migrating Neotropical birds will be passing through the northeastern United States including the lower Susquehanna valley.  Hawk watches are staffed and observers are awaiting big flights of Broad-winged Hawks—hoping to see a thousand birds or more in a single day.

During its passage through the Lower Susquehanna River Watershed, an adult Broad-winged Hawk sails over Second Mountain Hawk Watch in Lebanon County, Pennsylvania.
A hatch-year/juvenile Broad-winged Hawk gazes toward hawk watchers on the ground.

Broad-winged hawks feed on rodents, amphibians, and a variety of large insects while on their breeding grounds in the forests of the northern United States and Canada.  They depart early, journeying to wintering areas in Central and South America before frost robs them of a reliable food supply.

The Carolina Saddlebags (Tramea carolina), this one photographed at Second Mountain Hawk Watch on September 8th, is the rarest of the lower Susquehanna region’s migratory dragonflies.  Autumn Broad-winged Hawk movements coincide with southbound flights of the Carolina Saddlebags and the more numerous migratory dragonfly species: Common Green Darner, Wandering Glider, Twelve-spotted Skimmer, and Black Saddlebags.  “Broad-wings” will often eat these and other dragonflies during migration and can sometimes be seen catching and feeding upon them while still soaring high overhead.

While migrating, Broad-winged Hawks climb to great altitudes on thermal updrafts and are notoriously difficult to see from ground level.  Bright sunny skies with no clouds to serve as a backdrop further complicate a hawk counter’s ability to spot passing birds.  Throughout the Lower Susquehanna River Watershed, the coming week promises to be especially challenging for those trying to observe and census the passage of high-flying Broad-winged Hawks.  The forecast of hot and humid weather is not so unusual, but the addition of smoke from fires in the western states promises to intensify the haze and create an especially irritating glare for those searching the skies for raptors.

Smoke from fires along the California coast and in central Utah can be seen streaming east this morning.  (NOAA/GOES image)
Smoke from western fires and humid air creates a band of haze in Ohio, Pennsylvania, New Jersey, and states to the south this morning.   (NOAA/GOES image)

 

A migrating Broad-winged Hawk in the glare of a hazy sky.  In addition to visibility problems, swarms of Spotted Lanternflies above the treetops make distant hawks difficult to discern for hawk watchers scanning the horizon with binoculars.

It may seem gloomy for the mid-September flights in 2021, but hawk watchers are hardy types.  They know that the birds won’t wait.  So if you want to see migrating “Broad-wings” and other species, you’ve got to get out there and look up while they’re passing through.

Migrating Ospreys typically fly low enough and are large enough to be spotted even during the haziest of conditions.
Bald Eagles like this fourth-year bird can ascend to great altitude, but their size usually prevents them from sneaking past a lookout unnoticed.
Peregrines escape notice not due to hazy sky conditions, but because they pass by so quickly.  They’re being seen at local hawk watches now through October.

These hawk watches in the Lower Susquehanna River Watershed are currently staffed by official counters and all welcome visitors:

    • Rocky Ridge County Park Hawk Watch—3699 Deininger Road off Mount Zion Road (Route 24) northeast of York, Pennsylvania.
    • Second Mountain Hawk Watch—off Cold Spring Road on the grounds of Fort Indiantown Gap in Lebanon County, Pennsylvania.
    • Waggoner’s Gap Hawk Watch—where Route 74 crosses Blue Mountain north of Carlisle, Pennsylvania.

—or you can just keep an eye on the sky from wherever you happen to be.  And don’t forget to check the trees and shrubs because warbler numbers are peaking too!  During recent days…

Northern Parula at Chiques Rock County Park in Lancaster County.
Black-and-white Warbler at Rocky Ridge County Park in York County.
Cape May Warbler at Chiques Rock County Park in Lancaster County.
Bay-breasted Warbler at Rocky Ridge County Park in York County.

Shorebirds at Middle Creek

Late August and early September is prime time to see migrating shorebirds as they pass through the lower Susquehanna valley during their autumn migration, which, believe it or not, can begin as early as late June.  These species that are often assumed to spend their lives only near the seashore are regular visitors each fall as they make their way from breeding grounds in the interior of Canada to wintering sites in seacoast wetlands—many traveling as far south as Central and South America.

Low water levels on the Susquehanna River often coincide with the shorebird migration each year, exposing gravel and sand bars as well as vast expanses of muddy shorelines as feeding and resting areas for these traveling birds.  This week though, rain from the remnants of Tropical Storm Fred arrived to increase the flow in the Susquehanna and inundate most of the natural habitat for shorebirds.  Those on the move must either continue through the area without stopping or find alternate locations to loaf and find food.

The draining and filling of wetlands along the river and elsewhere in the region has left few naturally-occurring options.  The Conejohela Flats south of Columbia offer refuge to many migrating sandpipers and their allies, the river level there being controlled by releases from the Safe Harbor Dam during all but the severest of floods.  Shorebirds will sometimes visit flooded fields, but wide-open puddles and farmland resembling mudflats is more of springtime occurrence—preceding the planting and growth of crops.  Well-designed stormwater holding facilities can function as habitat for sandpipers and other wildlife.  They are worth checking on a regular basis—you never know what might drop in.

Right now, there is a new shorebird hot spot in the Lower Susquehanna River Watershed—Middle Creek Wildlife Management Area.  The water level in the main impoundment there has been drawn down during recent weeks to expose mudflats along the periphery of nearly the entire lake.  Viewing from “Stop 1” (the roadside section of the lake in front of the refuge museum) is best.  The variety of species and their numbers can change throughout the day as birds filter in and out—at times traveling to other mudflats around the lake where they are hidden from view.  The birds at “Stop 1” are backlit in the morning with favorable illumination developing in the afternoon.

Have a look at a few of the shorebirds currently being seen at Middle Creek…

The Killdeer is familiar as a breeding bird in the lower Susquehanna region.  Large numbers can congregate ahead of and during migration on mudflats and gravel bars.
The Least Sandpiper is one of the “peeps”, a group of very small shorebirds.  This species is quite common at Middle Creek right now.  Note the plants beginning to grow in the mud.  Later in the fall, after the shorebirds are gone, raising the water level in the lake will flood these newly vegetated areas to provide an abundance of food for migrating waterfowl.  This cycle can be repeated annually to support transient birds during what is often the most vulnerable time of their lives…fall migration.
The Baird’s Sandpiper (Calidris bairdii) is an uncommon “peep” along the east coast during autumn migration.  On the lower Susquehanna it is most frequently encountered on the vegetated gravel bars in mid-river during the last days of August or first days of September each year.  The mudflats and shallows at Middle Creek are providing a suitable alternative for this juvenile bird.
Numbers of Lesser Yellowlegs are increasing as flocks drop by for a rest and refueling.  Bring your binoculars and your spotting scope to see the oddities that may be hiding among these groups of newly-arriving migrants.

The aquatic environs at Middle Creek attract other species as well.   Here are some of the most photogenic…

Wood Ducks atop the dam.
The migration of Caspian Terns coincides with that of shorebirds.  Just look at that blood-red bill; it’s unmistakable.  Two of these big terns are currently patrolling Middle Creek’s lake and shoreline.
A female American Kestrel creates a stir among the “peeps” as it passes by.  The larger falcons (the Merlin and Peregrine) can be expected to more readily take advantage of concentrations of shorebirds as a food supply.
Osprey migration is underway, and many will stop at Middle Creek while in transit.
Even if shorebirds aren’t your thing, there are almost always Bald Eagles to be seen at Middle Creek.  See you there!

Conowingo Dam: Cormorants, Eagles, Snakeheads and a Run of Hickory Shad

Meet the Double-crested Cormorant,  a strangely handsome bird with a special talent for catching fish.  You see, cormorants are superb swimmers when under water—using their webbed feet to propel and maneuver themselves with exceptional speed in pursuit of prey.

Like many species of birds that dive for their food, Double-crested Cormorants run across the surface of the water to gain speed for a takeoff.  Smaller wings may make it more difficult to get airborne, but when folded, they provide improved streamlining for submerged swimming.

Double-crested Cormorants, hundreds of them, are presently gathered along with several other species of piscivorous (fish-eating) birds on the lower Susquehanna River below Conowingo Dam near Rising Sun, Maryland.  Fish are coming up the river and these birds are taking advantage of their concentrations on the downstream side of the impoundment to provide food to fuel their migration or, in some cases, to feed their young.

Double-crested Cormorants, mostly adult birds migrating toward breeding grounds to the north, are gathered on the rocks on the east side of the river channel below Conowingo Dam.  A Great Blue Heron from a nearby rookery can be seen at the center of the image.
Bald Eagles normally gather in large numbers at Conowingo Dam in the late fall and early winter.  Presently there are more than 50 there, and the majority of them are breeding age adults.  Presumably they are still on their way north to nest.  Meanwhile, local pairs are already feeding young, so it seems these transient birds are running a bit late.  Many of them can be seen on the rocks along the east side of the river channel,…
…on the powerline trestles on the island below the dam…
…in the trees along the east shore,…
…and in the trees surrounding Fisherman’s Park on the west shore.

In addition to the birds, the movements of fish attract larger fish, and even larger fishermen.

Anglers gather to fish the placid waters below the dam’s hydroelectric powerhouse .  Only a few of the generating turbines are operating, so the flow through the dam is minimal.
Some water is being released along the west shoreline to attract migratory river herring to the west fish lift for sorting and retention as breeding stock for a propagation program.  The east lift, the passage that hoists American Shad (Alosa sapidissima) to a trough that allows them to swim over the top of the dam to waters upriver, will begin operating as soon as these larger migratory fish begin arriving.

The excitement starts when the sirens start to wail and the red lights begin flashing.  Yes friends, it’s showtime.

Red lights and sirens are a warning that additional flow is about to be released from the dam.  Boaters should anticipate rough water and persons in and along the river need to seek higher ground immediately.
Gates are opened at mid-river to release a surge of water through the dam.
The wake from the release quickly reaches the shoreline, raising the water level in moments.
Experienced anglers know that the flow through the dam gets fish moving and can improve the catch significantly, especially in spring when many species are ascending the river.

Within minutes of the renewed flow, birds are catching fish.

A Double-crested Cormorant with a young Channel Catfish (Ictalurus punctatus).
A Double-crested Cormorant fleeing others trying to steal its Channel Catfish.
Another Double-crested Cormorant eating a Channel Catfish.  Did you realize that Channel Catfish were an introduced species in the Susquehanna River system?
An Osprey with a stick, it’s too busy building a nest right now to fish.
Great Blue Herons swallow their prey at the spot of capture, then fly back to the nest to regurgitate a sort of “minced congealed fish product” to their young.

Then the anglers along the wave-washed shoreline began catching fish too.

This young man led off a flurry of catches that would last for the remainder of the afternoon.
Though Gizzard Shad are filter feeders that don’t readily take baits and lures, they are regularly foul-hooked and reeled in from the large schools that ascend the river in spring.
Gizzard Shad are very abundant in the lower Susquehanna, providing year-round forage for many species of predatory animals including Bald Eagles.
A Double-crested Cormorant swallowing a Gizzard Shad.
This angler soon helped another fisherman by landing his large catch, a Northern Snakehead (Channa argus).
The teeth of a Northern Snakehead are razor sharp.  It is an aggressive non-native invasive species currently overtaking much of the Lower Susquehanna River Watershed.  Anglers are encouraged to fish for them, catch them, keep them, and kill them at the site of capture.  Never transport a live Northern Snakehead  anywhere at any time.  It is illegal in both Maryland and Pennsylvania to possess a live snakehead. 
Northern Snakehead advisory sign posted at Exelon Energy’s Conowingo Fishermen’s Park.
A stringer of Northern Snakeheads.  This species was imported from Asia as a food fish, so it has excellent culinary possibilities.  It’s better suited for a broiler or frying pan than a river or stream.
Another stringer of Northern Snakeheads.  It’s pretty safe to say that they have quickly become one of the most abundant predatory fish in the river.  Their impact on native species won’t be good, so catch and eat as many as you can.  Remember, snakeheads swim better in butter and garlic than in waters with native fish.
This foul-hooked Shorthead Redhorse (Moxostoma macrolepidotum), a native species of sucker, was promptly released.
Striped Bass are anadromous fish that leave the sea in spring to spawn in fresh water.  They ascend the Susquehanna in small numbers, relying upon the operation of the fish passages at the Conowingo, Holtwood, Safe Harbor, and York Haven Dams to continue their journey upstream.  During spring spawning, Striped Bass in the Susquehanna River and on the Susquehanna Flats portion of the upper Chesapeake Bay are not in season and may not be targeted, even for catch-and-release.  This accidental catch was immediately turned loose.
After removal from the hook, this hefty Smallmouth Bass was returned to the river.  Many anglers are surprised to learn that Smallmouth Bass are not native to the Susquehanna basin.
This angler’s creel contains a Northern Snakehead (left) and a Walleye (right).  Did you know that the Walleye (Sander vitreus) is an introduced species in the Susquehanna watershed?
By late afternoon, anglers using shad darts began hooking into migrating Hickory Shad (Alosa mediocris), a catch-and-release species in Maryland.
Hickory Shad are recognized by their lengthy lower jaw.  They are anadromous herring that leave the sea to spawn in freshwater streams.  Hickory Shad ascend the Susquehanna as far as Conowingo Dam each year, but shy away from the fish lifts.  Downriver from the dam, they do ascend Deer Creek along the river’s west shore and Octoraro Creek on the east side.  In Pennsylvania, the Hickory Shad is an endangered species.
A Hickory Shad angled on a dual shad dart rig.  During the spring spawning run, they feed mostly on small fish, and are the most likely of the Susquehanna’s herring to take the hook.
Simultaneous hook-ups became common after fours hours worth of release water from the dam worked its way toward the mouth of the river and got the schools moving.  Water temperatures in the mid-to-upper-fifties trigger the ascent of Hickory Shad.  On the Susquehanna, those temperatures were slow to materialize in the spring of 2021, so the Hickory Shad migration is a bit late.
Catch-and-release fishing for Hickory Shad appears to be in full swing not only at the dam, but along the downstream shoreline to at least the mouth of Deer Creek at Susquehanna State Park too.
Many Hickory Shad could be seen feeding on some of the millions of caddisflies (Trichoptera) swarming on the river.  These insects, along with earlier hatches of Winter Stoneflies (Taeniopterygidae), not only provide forage for many species of fish, but  are a vital source of natural food for birds that migrate up the river in March and April each year.  Swallows, Ring-billed Gulls, and Bonaparte’s Gulls are particularly fond of snatching them from the surface of the water.
A Winter Stonefly (Taeniopterygidae) from an early-season hatch on the Susquehanna River at the Veteran’s Memorial Bridge at Columbia/Wrightsville, Pennsylvania.  (March 3, 2021)
Just below Conowingo Dam, a lone fly fisherman was doing a good job mimicking the late-April caddisfly hatch, successfully reeling in numerous surface-feeding Hickory Shad.
You may have noticed the extraordinary number of introduced fish species listed in this account of a visit to Conowingo Dam.  Sorry to say that there are two more: the Flathead Catfish (Pylodictis olivaris) and the Blue Catfish (Ictalurus furcatus).  Like the Northern Snakehead, each has become a plentiful invasive species during recent years.  Unlike the Northern Snakehead, these catfish are “native transplants”, species introduced from populations in the Mississippi River and Gulf Slope drainages of the United States.  So if you visit the area, consider getting a fishing license and catching a few.  Like the snakeheads, they too are quite palatable.

The arrival of migrating Hickory Shad heralds the start of a movement that will soon include White Perch, anadromous American Shad, and dozens of other fish species that swim upstream during the springtime.  Do visit Fisherman’s Park at Conowingo Dam to see this spectacle before it’s gone.  The fish and birds have no time to waste, they’ll soon be moving on.

To reach Exelon’s Conowingo Fisherman’s Park from Rising Sun, Maryland, follow U.S. Route 1 south across the Conowingo Dam, then turn left onto Shuresville Road, then make a sharp left onto Shureslanding Road.  Drive down the hill to the parking area along the river.  The park’s address is 2569 Shureslanding Road, Darlington, Maryland.

A water release schedule for the Conowingo Dam can be obtained by calling Exelon Energy’s Conowingo Generation Hotline at 888-457-4076.  The recording is updated daily at 5 P.M. to provide information for the following day.

And remember, the park can get crowded during the weekends, so consider a weekday visit.

2020: A Good Year

You say you really don’t want to take a look back at 2020?  Okay, we understand.  But here’s something you may find interesting, and it has to do with the Susquehanna River in 2020.

As you may know, the National Weather Service has calculated the mean temperature for the year 2020 as monitored just upriver from Conewago Falls at Harrisburg International Airport.  The 56.7° Fahrenheit value was the highest in nearly 130 years of monitoring at the various stations used to register official climate statistics for the capital city.  The previous high, 56.6°, was set in 1998.

Though not a prerequisite for its occurrence, record-breaking heat was accompanied by a drought in 2020.  Most of the Susquehanna River drainage basin experienced drought conditions during the second half of the year, particularly areas of the watershed upstream of Conewago Falls.  A lack of significant rainfall resulted in low river flows throughout late summer and much of the autumn.  Lacking water from the northern reaches, we see mid-river rocks and experience minimal readings on flow gauges along the lower Susquehanna, even if our local precipitation happens to be about average.

Back in October, when the river was about as low as it was going to get, we took a walk across the Susquehanna at Columbia-Wrightsville atop the Route 462/Veteran’s Memorial Bridge to have a look at the benthos—the life on the river’s bottom.

As we begin our stroll across the river, we quickly notice Mallards and a Double-crested Cormorant (far left) feeding among aquatic plants.  You can see the leaves of the vegetation just breaking the water’s surface, particularly behind the feeding waterfowl.  Let’s have a closer look.
An underwater meadow of American Eelgrass (Vallisneria americana) as seen from atop the Veteran’s Memorial Bridge at Columbia-Wrightsville.  Also known as Freshwater Eelgrass, Tapegrass, and Wild Celery, it is without a doubt the Susquehanna’s most important submerged aquatic plant.  It grows in alluvial substrate (gravel, sand, mud, etc.) in river segments with moderate to slow current.  Water three to six feet deep in bright sunshine is ideal for its growth, so an absence of flooding and the sun-blocking turbidity of muddy silt-laden water is favorable.
Plants in the genus Vallisneria have ribbon-like leaves up to three feet in length that grow from nodes rooted along the creeping stems called runners.  A single plant can, over a period of years, spread by runners to create a sizable clump or intertwine with other individual plants to establish dense meadows and an essential wildlife habitat.
An uprooted segment of eelgrass floats over a thick bed of what may be parts of the same plant.  Eelgrass meadows on the lower Susquehanna River were decimated by several events: deposition of anthracite coal sediments (culm) in the late-nineteenth and early-twentieth centuries, dredging of the same anthracite coal sediments during the mid-twentieth century, and the ongoing deposition of sediments from erosion occurring in farm fields, logged forests, abandoned mill ponds, and along denuded streambanks.  Not only has each of these events impacted the plants physically by either burying them or ripping them out by the roots, each has also contributed to the increase in water turbidity (cloudiness) that blocks sunlight and impairs their growth and recovery.
A submerged log surrounded by beds of eelgrass forms a haven for fishes in sections of the river lacking the structure found in rock-rich places like Conewago Falls.  A period absent of high water and sediment runoff extended through the growing season in 2020 to allow lush clumps of eelgrass like these to thrive and further improve water quality by taking up nutrients, particularly nitrogen and phosphorus.  Nutrients used by vascular plants including eelgrass become unavailable for feeding detrimental algal blooms in downstream waters including Chesapeake Bay.
Small fishes and invertebrates attract predatory fishes to eelgrass beds.  We watched this Smallmouth Bass leave an ambush site among eelgrass’s lush growth to shadow a Common Carp as it rummaged through the substrate for small bits of food.  The bass would snatch up crayfish that darted away from the cover of stones disturbed by the foraging carp.
Sunfishes are among the species taking advantage of eelgrass beds for spawning.  They’ll build a nest scrape in the margins between clumps of plants allowing their young quick access to dense cover upon hatching.  The abundance of invertebrate life among the leaves of eelgrass nourishes feeding fishes, and in turn provides food for predators including Bald Eagles, this one carrying a freshly-caught Bluegill.

These improvements in water quality and wildlife habitat can have a ripple effect.  In 2020, the reduction in nutrient loads entering Chesapeake Bay from the low-flowing Susquehanna may have combined with better-than-average flows from some of the bay’s lesser-polluted smaller tributaries to yield a reduction in the size of the bay’s oxygen-deprived “dead zones”.  These dead zones typically occur in late summer when water temperatures are at their warmest, dissolved oxygen levels are at their lowest, and nutrient-fed algal blooms have peaked and died.  Algal blooms can self-enhance their severity by clouding water, which blocks sunlight from reaching submerged aquatic plants and stunts their growth—making quantities of unconsumed nutrients available to make more algae.  When a huge biomass of algae dies in a susceptible part of the bay, its decay can consume enough of the remaining dissolved oxygen to kill aquatic organisms and create a “dead zone”.  The Chesapeake Bay Program reports that the average size of this year’s dead zone was 1.0 cubic miles, just below the 35-year average of 1.2 cubic miles.

Back on a stormy day in mid-November, 2020, we took a look at the tidal freshwater section of Chesapeake Bay, the area known as Susquehanna Flats, located just to the southwest of the river’s mouth at Havre de Grace, Maryland.  We wanted to see how the restored American Eelgrass beds there might have fared during a growing season with below average loads of nutrients and life-choking sediments spilling out of the nearby Susquehanna River.  Here’s what we saw.

We followed the signs from Havre de Grace to Swan Harbor Farm Park.
Harford County Parks and Recreation’s Swan Harbor Farm Park consists of a recently-acquired farming estate overlooking the tidal freshwater of Susquehanna Flats.
Along the bay shore, a gazebo and a fishing pier have been added.  Both provide excellent observation points.
The shoreline looked the way it should look on upper Chesapeake Bay, a vegetated buffer and piles of trees and other organic matter at the high-water line.  There was less man-made garbage than we might find following a summer that experienced an outflow from river flooding, but there was still more than we should be seeing.
Judging by the piles of fresh American Eelgrass on the beach, it looks like it’s been a good year.  Though considered a freshwater plant, eelgrass will tolerate some brackish water, which typically invades upper Chesapeake Bay each autumn due to a seasonal reduction in freshwater inflow from the Susquehanna and other tributaries.  Saltwater can creep still further north when the freshwater input falls below seasonal norms during years of severe drought.  The Susquehanna Flats portion of the upper bay very rarely experiences an invasion by brackish water; there was none in 2020.
As we scanned the area with binoculars and a spotting scope, a raft of over one thousand ducks and American Coots (foreground) could be seen bobbing among floating eelgrass leaves and clumps of the plants that had broken away from their mooring in the mud.  Waterfowl feed on eelgrass leaves and on the isopods and other invertebrates that make this plant community their home.
While coots and grebes seemed to favor the shallower water near shore, a wide variety of both diving and dabbling ducks were widespread in the eelgrass beds more distant.  Discernable were Ring-necked Ducks, scaup, scoters, Long-tailed Ducks, Redheads, American Wigeons, Gadwall, Ruddy Ducks, American Black Ducks, and Buffleheads.

We noticed a few Canvasbacks (Aythya valisineria) on the Susquehanna Flats during our visit.  Canvasbacks are renowned as benthic feeders, preferring the tubers and other parts of submerged aquatic plants (a.k.a. submersed aquatic vegetation or S.A.V.) including eelgrass, but also feeding on invertebrates including bivalves.  The association between Canvasbacks and eelgrass is reflected in the former’s scientific species name valisineria, a derivitive of the genus name of the latter, Vallisneria.

Canvasbacks on Chesapeake Bay.  (United States Fish and Wildlife Service image by Ryan Hagerty)

The plight of the Canvasback and of American Eelgrass on the Susquehanna River was described by Herbert H. Beck in his account of the birds found in Lancaster County, Pennsylvania, published in 1924:

“Like all ducks, however, it stops to feed within the county less frequently than formerly, principally because the vast beds of wild celery which existed earlier on broads of the Susquehanna, as at Marietta and Washington Borough, have now been almost entirely wiped out by sedimentation of culm (anthracite coal waste).  Prior to 1875 the four or five square miles of quiet water off Marietta were often as abundantly spread with wild fowl as the Susquehanna Flats are now.”

Beck quotes old Marietta resident and gunner Henry Zink:

“Sometimes there were as many as 500,000 ducks of various kinds on the Marietta broad at one time.”

The abundance of Canvasbacks and other ducks on the Susquehanna Flats would eventually plummet too.  In the 1950s, there were an estimated 250, 000 Canvasbacks wintering on Chesapeake Bay, primarily in the area of the American Eelgrass, a.k.a. Wild Celery, beds on the Susquehanna Flats.  When those eelgrass beds started disappearing during the second half of the twentieth century, the numbers of Canvasbacks wintering on the bay took a nosedive.  As a population, the birds moved elsewhere to feed on different sources of food, often in saltier estuarine waters.

Canvasbacks were able to eat other foods and change their winter range to adapt to the loss of habitat on the Susquehanna River and Chesapeake Bay.  But not all species are the omnivores that Canvasbacks happen to be, so they can’t just change their diet and/or fly away to a better place.  And every time a habitat like the American Eelgrass plant community is eliminated from a region, it fragments the range for each species that relied upon it for all or part of its life cycle.  Wildlife species get compacted into smaller and smaller suitable spaces and eventually their abundance and diversity are impacted.  We sometimes marvel at large concentrations of birds and other wildlife without seeing the whole picture—that man has compressed them into ever-shrinking pieces of habitat that are but a fraction of the widespread environs they once utilized for survival.  Then we sometimes harass and persecute them on the little pieces of refuge that remain.  It’s not very nice, is it?

By the end of 2020, things on the Susquehanna were getting back to normal.  Near normal rainfall over much of the watershed during the final three months of the year was supplemented by a mid-December snowstorm, then heavy downpours on Christmas Eve melted it all away.  Several days later, the Susquehanna River was bank full and dishing out some minor flooding for the first time since early May.  Isn’t it great to get back to normal?

The rain-and-snow-melt-swollen Susquehanna from Chickies Rock looking upriver toward Marietta during the high-water crest on December 27th.
Cresting at Columbia as seen from the Route 462/Veteran’s Memorial Bridge.  A Great Black-backed Gull monitors the waters for edibles.
All back to normal on the Susquehanna to end 2020.
Yep, back to normal on the Susquehanna.  Maybe 2021 will turn out to be another good year, or maybe it’ll  just be a Michelin or Firestone.

SOURCES

Beck, Herbert H.  1924.  A Chapter on the Ornithology of Lancaster County, Pennsylvania.  The Lewis Historical Publishing Company.  New York, NY.

White, Christopher P.  1989.  Chesapeake Bay, Nature of the Estuary: A Field Guide.  Tidewater Publishers.  Centreville, MD.

City Life: Gulls, Dabbling Ducks, and More

So you aren’t particularly interested in a stroll through the Pennsylvania woods during the gasoline and gunpowder gang’s second-biggest holiday of the year—the annual sacrifice-of-the-White-tailed-Deity ritual.  I get it.  Two weeks and nothing to do.  Well, why not try a hike through the city instead?  I’m not kidding.  You might be surprised at what you see.  Here are some photographs taken today during several strolls in Harrisburg, Pennsylvania.

First stop was City Island in the Susquehanna River—accessible from downtown Harrisburg or the river’s west shore by way of the Market Street Bridge.

From the middle of the Susquehanna River, City Island offers a spectacular view of the downtown Harrisburg skyline.  In summer, it’s the capital city’s playground.  During the colder months, it’s a great place to take a quiet walk and find unusual birds.
This Bald Eagle was in mature trees along the river shoreline near the Harrisburg Senator’s baseball stadium.
Ring-billed Gulls gather on the “cement beach” at the north end of City Island.
One of a dozen or so Herring Gulls seen from the island’s north end. This particular bird is a juvenile.
A Ring-billed Gull and some petite Bonaparte’s Gulls.  Really good birders will tell you to always check through flocks of these smaller gulls carefully.  It turns out they’re onto something.  Look closely at the gull to the right.
A bright red bill and more of a crescent shape to the black spot behind the eye, that’s an adult Black-headed Gull (Chroicocephalus ridibundus) in winter plumage, a rare bird on the Susquehanna.  Black-headed Gulls have colonized North America from Europe, breeding in Iceland, southernmost Greenland, and rarely Newfoundland.

Okay, City Island was worth the effort.  Next stop is Wildwood Park, located along Industrial Road just north of the Pennsylvania Farm Show complex and the Harrisburg Area Community College (HACC) campus.  There are six miles of trails surrounding mile-long Wildwood Lake within this marvelous Dauphin County Parks Department property.

A flock of Killdeer at the south end of Wildwood Lake.  From November through February, a walk along the south and west sides of the impoundment can be a photographer’s dream. The light is suitable in the morning, then just keeps getting better as the day wears on.
Is this probable Carolina/Black-capped Chickadee hybrid a resident at Wildwood or just a visitor from a few miles to the north?  Currently, pure Black-capped Chickadees (Poecile atricapillus) nest in the mountains well to the north of Harrisburg, and pure Carolina Chickadees nest south of the city.  Harrisburg possibly remains within the intergrade/hybrid zone, an area where the ranges of the two species overlap, but probably not for long.  During recent decades, this zone has been creeping north, at times by as much as a half mile or more each year.  So if the capital city isn’t Carolina Chickadee territory yet, it soon will be.
Another chickadee likely to be a hybrid, this one with some white in the greater wing coverts like a Black-capped, but with a call even more rapid than that of the typical Carolina, the species known for uttering the faster “chick-a-dee-dee-dee”.  It sounded wired, like it had visited a Starbucks all morning.
In the lower Susquehanna valley, Carolina Chickadees have already replaced hybrids and pure Black-capped Chickadees as nesting birds in the Piedmont hills south of Harrisburg and the Great Valley.  This Carolina Chickadee was photographed recently in the Furnace Hills at Middle Creek Wildlife Management Area in northern Lancaster County.  The transition there was probably complete by the end of the twentieth century.  Note the characteristic overall grayish appearance of the wings and the neat lower border of the black bib on this bird, 
For comparison, a bird presumed to be a pure Black-capped Chickadee photographed earlier this month in Lebanon County, Pennsylvania.  This fall, “Black-caps”, like many other northern perching birds, are moving south to invade the lower elevations and milder climes of the Piedmont and Atlantic Coastal Plain Provinces.  Note the extensive areas of white in the wings, the long tail, the buffy flanks, and the jagged edge of the black bib.
Along Wildwood Lake’s west shore, an adult male Sharp-shinned Hawk was soon attracted to the commotion created by bantering chickadees and other songbirds.
Yellow during the first year, the eyes of the Sharp-shinned Hawk get redder as the bird ages.
Also along the west border of Wildwood Lake, temperatures were warm enough to inspire Painted Turtles (Chrysemys picta) to seek a sun bath atop logs in the flooded portions of the abandoned Pennsylvania Canal.

And now, without further ado, it’s time for the waterfowl of Wildwood Lake—in order of their occurrence.

A pair of Wood Ducks (hen left, drake right) with American Black Ducks and Canada Geese.
A pair of Northern Pintails.
A pair of American Wigeons (Mareca americana).
A hen (left) and drake (right) Gadwall.
Mallards.
A female Northern Shoveler.
An American Black Duck.
Canada Geese.
You just knew there had to be a booby prize, a “Blue Suede” (a.k.a. Blue Swede), a domestic variety of Mallard.
It’s a Green-winged Teal (Anas crecca) sampler.  Clockwise from left: a juvenile male, a female, and an adult male.
A drake and two hen Green-winged Teal.  Isn’t that great light by late afternoon?

See, you don’t have to cloak yourself in bright orange ceremonial garments just to go for a hike.  Go put on your walking shoes and a warm coat, grab your binoculars and/or camera, and have a look at wildlife in a city near you.  You never know what you might find.

SOURCES

Taylor, Scott A., Thomas A. White, Wesley M. Hochachka, Valentina Ferretti, Robert L. Curry, and Irby Lovette.  2014.  “Climate-Mediated Movement of an Avian Hybrid Zone”.  Current Biology.  24:6  pp.671-676.

Bald Eagles Arriving at Conowingo Dam

You need to see this to believe it—dozens, sometimes hundreds, of Bald Eagles doing their thing and you can stand or sit in just one place to take it all in.

Conowingo Dam on the Susquehanna River near Darlington, Maryland, attracts piscivores galore.  Young Gizzard Shad (Dorosoma cepedianum) and other small fishes are temporarily stunned as they pass through the turbines and gated discharges at the hydroelectric facility’s power house.  Waiting for them in the rapids below are predatory fishes including Striped Bass (Morone saxatilis), White Perch (Morone americana), several species of catfishes, and more.  From above, fish-eating birds are on the alert for a disoriented turbine-traveler they can easily seize for a quick meal.

U.S. Route 1 crosses the Susquehanna River atop the Conowingo Dam.  Conowingo Fisherman’s Park, the observation site for the dam’s Bald Eagles and other birds, is located downstream of the turbine building along the river’s west (south) shore.  As the name implies, the park is a superb location for angling.
Heed this warning.  Close your windows and sunroof or the vultures will subject your vehicle’s contents to a thorough search for food.  Then they’ll deposit a little consolation prize on your paint.
Scavenging Black Vultures congregate by the hundreds at Conowingo Dam to clean up the scraps left behind by people and predators.  They’ll greet you right in the parking lot.
Photographers line up downstream of the turbine building for an opportunity to get the perfect shot of a Bald Eagle.
The operator of the Conowingo Hydroelectric Generating Station, Exelon Energy, provides clean comfortable facilities for fishing, sightseeing, and wildlife observation.
There’s almost always a Peregrine Falcon zooming around the dam to keep the pigeons on their toes.
Double-crested Cormorants on the boulders that line the channel below the dam.  Hundreds are there right now.
Double-crested Cormorants dive for fish near the power house discharge, which, while just one small generator is operating, seems nearly placid.  The feeding frenzy really gets going when Conowingo begins generating with multiple large turbines and these gently flowing waters become torrential rapids filled with disoriented fishes.
Ring-billed Gulls seek to snag a small fish from the water’s surface.
After successfully nabbing shad or perch, these Double-crested Cormorants need to swallow their catch fast or risk losing it.  Stealing food is a common means of survival for the gulls, eagles, and other birds found here.
Where do migrating eagles go?  There are, right now, at least 50 Bald Eagles at Conowingo Dam, with more arriving daily.  Numbers are likely to peak during the coming weeks.
Eagles can be seen perched in the woods along both river shorelines, even in the trees adjacent to the Conowingo Fisherman’s Park car lot.  Others take stand-by positions on the boulders below the dam.
To remind visiting eagles that they are merely guests at Conowingo, a resident Bald Eagle maintains a presence at its nest on the wooded slope above Fisherman’s Park.  Along the lower Susquehanna, female Bald Eagles lay eggs and begin incubation in January.
When an eagle decides to venture out and attempt a dive at a fish, that’s when the photographers rush to their cameras for a chance at a perfect shot.
The extraordinary concentrations of Bald Eagles at Conowingo make it an excellent place to study the plumage differences between birds of various ages.
Here’s a first-year Bald Eagle, also known as a hatch-year or juvenile bird.
A second-year or Basic I immature Bald Eagle.  Note the long juvenile secondaries giving the wings a ragged-looking trailing edge.
A third-year or Basic II immature Bald Eagle.
A second-year/Basic I immature Bald Eagle (top) and a third-year/Basic II immature Bald Eagle (bottom).
A second-year/Basic I immature Bald Eagle (bottom) and a third-year/Basic II immature Bald Eagle (top).  Note the white feathers on the backs of eagles in these age classes.
A third-year/Basic II immature Bald Eagle perched in a tree alongside the parking area.  Note the Osprey-like head plumage.
A sixth-year or older adult Bald Eagle in definitive plumage (left) and a fourth-year or Basic III immature Bald Eagle (right).
If you want to see the Bald Eagles at Conowingo Dam, don’t wait.  While many birds are usually present throughout the winter, the large concentrations may start dispersing as early as December when eagles begin wandering in search of other food sources, particularly if the river freezes.
A pair of Bald Eagles is already working on a nest atop this powerline trestle downstream of Conowingo Dam.  By late December, most adult eagles will depart Conowingo to begin spending their days establishing and defending breeding territories elsewhere.  Any non-adult eagles still loitering around the dam will certainly begin receiving encouragement from the local nesting pair(s) to move along as well.

To reach Exelon’s Conowingo Fisherman’s Park from Rising Sun, Maryland, follow U.S. Route 1 south across the Conowingo Dam, then turn left onto Shuresville Road, then make a sharp left onto Shureslanding Road.  Drive down the hill to the parking area along the river.  The park’s address is 2569 Shureslanding Road, Darlington, Maryland.

As Bald Eagle numbers continue to increase, expect the parking lot to become full during weekends and over the Thanksgiving holiday.  To avoid the crowds, plan to visit during a weekday.

You can get the generating schedule for the Conowingo Dam by calling the Conowingo Generation Hotline at 888-457-4076.  The recording is updated daily at 5 P.M. to provide information for the following day.

Migrating Golden Eagles

Why would otherwise sensible people perch themselves atop a rocky outcrop on a Pennsylvania mountaintop for ten hours on a windy bone-numbing bitter cold and sometimes snowy November day?  To watch migrating raptors of course.

November is the time when big hawks and eagles migrate through and into the lower Susquehanna valley.  And big birds rely on big wind to create updrafts and an easy ride along the region’s many ridges.  The most observable flights often accompany the arrival of cold air surging across the Appalachian Mountains from the northwest.  These conditions can propel season-high numbers of several of the largest species of raptors past hawk-counting sites.

Observers brave howling winds on the Waggoner’s Gap lookout to census migrating late-season raptors.

Earlier this week, two windy days followed the passage of a cold front to usher-in spectacular hawk and eagle flights at the the Waggoner’s Gap Hawk Watch station on Blue Mountain north of Carlisle, Pennsylvania.  Steady 30 M.P.H. winds from the northwest on Monday, November 2, gusted to 50 M.P.H. at times.  Early that morning, two Rough-legged Hawks, rarities at eastern hawk watches, were seen.  They and two American Goshawks (Accipiter atricapillus) provided a preview of the memorable sightings to come.  Two dozen Golden Eagles migrated past the lookout that day.  Then on November 3, thirty Golden Eagles were tallied, despite west winds at speeds not exceeding half those of the day before.

Here are some of the late-season raptors seen by hardy observers at Waggoner’s Gap on Monday and Tuesday, November 2 & 3.

In November, Red-tailed Hawks are the most common migratory raptor counted at hawk watch stations in the Susquehanna region.
 A juvenile American Goshawk passes the Waggoner's Gap lookout.
An uncommon bird, a juvenile American Goshawk, passes the Waggoner’s Gap lookout.
An adult Golden Eagle circles on an updraft along the north face of Blue Mountain to gain altitude before continuing on its journey.
The plumage of juvenile and immature Golden Eagles often creates a sensation among crowds at a lookout.  Golden Eagles don’t attain a full set of adult feathers until their sixth year.  This individual is probably a juvenile, also known as a hatch-year or first-year bird.  At most, it could be in its second year.  Click the “Golden Eagle Aging Chart” tab on this page to learn more about these uncommon migrants and their molt sequences as they mature.
The gilded head feathers of a Golden Eagle glisten in the afternoon sun.
An adult Golden Eagle passing Waggoner’s Gap.  The population known as “Eastern Golden Eagles” winters in the Appalachian Mountains and, with increasing frequency, on the Piedmont and Atlantic Coastal Plain Provinces of the eastern United States, where it often subsists as a scavenger.
Another first-year (juvenile) or second-year Golden Eagle.
A local Red-tailed Hawk (top left) trying to bully a migrating Golden Eagle.  A dangerous business indeed.
Through December, Bald Eagles, presently the more common of our eagle species, are regular migrants at Waggoner’s Gap and other Susquehanna valley hawk watch sites.
Red-shouldered Hawks are reliable early November migrants.
An adult Red-shouldered Hawk from above.
And an adult Red-shouldered Hawk from below.
Though their numbers peak in early October, Sharp-shinned Hawks, particularly adults like this one, continue to be seen through early November.
A Northern Harrier on the glide path overhead.
Merlins, like other falcons, are more apt to be seen in late September and October, but a few trickle through in November.

While visiting a hawk watch, one will certainly have the opportunity to see other birds too.

Common Ravens are fascinating birds and regular visitors to the airspace around hawk watches.  Most are residents, but there appears to be some seasonal movement, particularly among younger birds.
Most people think of Common Loons as birds of northern lakes.  But loons spend their winters in the ocean surf, and to get there they fly in loose flocks over the Lower Susquehanna River Watershed each spring and fall.  They are regularly seen by observers at hawk watches.
Like ducks, geese, and swans, migrating Double-crested Cormorants assemble into aerodynamic V-shaped flocks to conserve energy.
Pine Siskins continue their invasion from the north.  Dozens of small flocks numbering 10 to 20 birds each continue to be seen and/or heard daily at Waggoner’s Gap.  A flock of Evening Grosbeaks (Coccothraustes vesperitinus), another irruptive species of “winter finch”, was seen there on November 3.

As a finale of sorts, near the close of the day on November 3, two Golden Eagles sailed past the north side of the Waggoner’s Gap lookout, one possessing what appeared to be a tracking transmitter on its back.  An effort was commenced by the official count staff to report the sighting to the entity monitoring the bird—to track down the tracker, so to speak.

A Golden Eagle with a backpack transmitter passing Waggoner’s Gap Hawk Watch at 3:39 P.M. Eastern Standard Time on November 3, 2020.

To see the count reports from Waggoner’s Gap and other hawk watches throughout North America, be certain to visit hawkcount.org

A Visit to Waggoner’s Gap

Nothing beats spending a day at a hawk watch lookout—except of course spending a day at a hawk watch lookout when the birds are parading through nonstop for hours on end.

Check out Waggoner’s Gap, a hawk count site located on the border of Cumberland and Perry Counties atop Blue Mountain just north of Carlisle, Pennsylvania.  It is by far the Lower Susquehanna River Watershed’s best location for observing large numbers of migrating raptors during the October and November flights.

Waggoner’s Gap is located where Route 74 crosses Blue Mountain north of Carlisle.
The entrance to a parking area for hawk watch visitors is designated by this sign located along Route 74 several hundred yards north of the summit of Blue Mountain.
Since acquiring the site in 2000, Audubon Pennsylvania has added improvements to expand the function of Waggoner’s Gap Hawk Watch to include education for both formal students and the public at large.
The site is named in honor of the late conservationist Clifford L. Jones, a business leader, a former Chairman of the Pennsylvania Public Utilities Commission, a cabinet secretary for six Pennsylvania governors (both major parties), a director on the boards of numerous conservation organizations, and an active birder.
Orange falcon silhouettes function as blazes for the trails that lead from the parking area to the lookout.  The trail and the lookout consist entirely of boulders.  Some of these move when stepped upon.  Others may be slick.  Use caution at all times.
The lookout at Waggoner’s Gap is staffed by official counters from August through December each year.  They are tasked with enumerating every migratory raptor’s passage during that period.
Sure-footed observers climb into a comfortable position among the Tuscarora quartzite boulders and begin watching the flight.
The view from the lookout is spectacular.  To the east, downtown Harrisburg can be seen in the distance.
During a recent afternoon with breezes from the “southwesterlies”, a steady stream of  migrating Sharp-shinned Hawks, including this juvenile, passed by the lookout.
Sharp-shinned Hawks were ready subjects for photography as they sailed on updrafts along the south side of the ridge.
An adult Sharp-shinned Hawk.
A second-year Sharp-shinned Hawk.
A Sharp-shinned Hawk below eye level.  Over 400 Sharp-shinned Hawks migrated past Waggoner’s Gap Hawk Watch on this particular early October day.
The local Turkey Vultures at Waggoner’s Gap seem ubiquitous at times.  They’re on the radio towers, they’re flying overhead, and a few are cruising the slopes below the crest.  But on the day of our recent visit, their numbers were eclipsed by the more than 300 “T.V.s” that migrated down the ridge.
Black Vultures, both migrants and local birds, are seen from the lookout.
Northern Harriers are a hawk watch favorite.  Their long uptilted wings, long tail, and white rump make them easy to identify, even for beginners.  Their plummeting numbers make them a treasured sighting for everyone.
A Red-tailed Hawk on a close approach.
A distant Red-shouldered Hawk.  Numbers of these migrants peak later in the season.
A Peregrine Falcon darts past the lookout.  Note the white forehead, throat, and breast.  This bird is probably a “Tundra Peregrine” (Falco peregrinus tundrius).  In the lower Susquehanna valley, this subspecies is strictly migratory, a transient in spring and fall.  “Tundra Peregrines” breed in the arctic and winter as far south as South America.
An immature Bald Eagle.  Waggoner’s Gap is a superb place for sighting eagles, especially on a breezy day.
Hundreds of Blue Jays filtered through as their southbound exodus continues.  Other songbirds of interest included Blue-headed Vireos (Vireo solitarius), Winter Wrens, Red-breasted Nuthatches, Pine Siskins, and both Ruby-crowned and Golden-crowned Kinglets.

Waggoner’s Gap is a hardy birder’s paradise.  During the latter portion of the season, excellent flights often occur on days that follow the passage of a cold front and have strong northwest winds.  But be prepared, it can be brutal on those rocks during a gusty late-October or early-November day after the leaves fall—so dress appropriately.

To see the daily totals for the raptor count at Waggoner’s Gap Hawk Watch and other hawk watches in North America, and to learn more about each site, be sure to visit hawkcount.org

A Visit to Rocky Ridge

Early October is prime time for hawk watching, particularly if you want to have the chance to see the maximum variety of migratory species.  In coming days, a few Broad-winged Hawks and Ospreys will still be trickling through while numbers of Sharp-shinned Hawks, Cooper’s Hawks, Northern Harriers, and falcons swell to reach their seasonal peak.  Numbers of migrating Red-tailed and Red-shouldered Hawks are increasing during this time and late-season specialties including Golden Eagles can certainly make a surprise early visit.

If you enjoy the outdoors and live in the southernmost portion of the lower Susquehanna valley, Rocky Ridge County Park in the Hellam Hills just northwest of York, Pennsylvania, is a must see.  The park consists of oak forest and is owned and managed by the York County Parks Department.  It features an official hawk watch site staffed by volunteers and park naturalists.  Have a look.

The hawk watch lookout is reached by following the well-marked trail at the north side of the large gravel parking area in the utility right-of-way at the end of the park entrance road (Deininger Road).
The Rocky Ridge Hawk Watch lookout includes outcrops of bedrock, a viewing deck, and grassy areas suitable for lawn chairs.
The bedrock at the lookout is an unusual quartz-cemented conglomerate that forms the Hellam Member at the base of the Cambrian Chickies Formation.
Experienced hawk watchers conduct an official count of raptors and other birds during the autumn migration in September and October each year.  Visitors are welcome.  The view is spectacular.  Check out the concrete columns glowing in the sun to the north of the lookout.
It’s the cooling towers at the Three Mile Island Nuclear Station and the smoke stacks at the Brunner Island Steam Generating Station.  Conewago Falls is located between the two.
Interpretive signage on the hawk watch deck includes raptor identification charts.
A migrating Osprey glides by the lookout.
Throughout the month, migrating Sharp-shinned Hawks will be flying in a southwesterly direction along ridges in the region, particularly on breezy days.  They are the most numerous raptor at hawk watches in the lower Susquehanna valley during the first half of October.
A Peregrine Falcon quickly passes the Rocky Ridge lookout.  These strong fliers often ignore the benefits provided by thermals and updrafts along our ridges and instead take a direct north to south route during migration.
A juvenile Red-tailed Hawk soars by.
And a little while later, an adult Red-tailed Hawk follows.
Bald Eagles, including both migratory and resident birds, are seen regularly from the Rocky Ridge lookout.
Other diurnal (daytime) migrants are counted at Rocky Ridge and some of the other regional hawk watches.  Massive flights of Blue Jays have been working their way through the lower Susquehanna valley for more than a week now.  Local hawk watches are often logging hundreds in a single day.
The utility right-of-way within which the Rocky Ridge Hawk Watch is located can be a great place to see nocturnal (nighttime) migrants while they rest and feed during the day.  Right now, Eastern Towhees are common there.
An uncommon sight, a shy Lincoln’s Sparrow (Melospiza lincolnii) in the utility right-of-way near the hawk watch lookout.  This and other nocturnal migrants will take full advantage of a clear moonlit night to continue their southbound journey.

If you’re a nature photographer, you might be interested to know that there are still hundreds of active butterflies in Rocky Ridge’s utility right-of-way.  Here are a few.

A Gray Hairstreak.
An American Copper (Lycaena phlaeas),

To see the daily totals for the raptor count at Rocky Ridge Hawk Watch and other hawk watches in North America, and to learn more about each site, be certain to visit hawkcount.org

Fire and Ice at Conewago Falls

This morning, the Lower Susquehanna River Watershed experienced remotely the effects of fire and ice.

At daybreak, the cold air mass that brought the first freeze of the season to northernmost New England gave us a taste of the cold with temperatures below 50 degrees throughout.

The air temperature at daybreak in the Gettysburg Basin east of Conewago Falls.

At sunrise, the cloudless sky had a peculiar overcast look with no warm glow on buildings, vegetation, and terrain.  Soon, the sun was well above the horizon, yet there was still a sort of darkness across the landscape.

Smoke from massive wildland fires in the Pacific Coast States created a haze that persisted throughout the day in the Susquehanna valley.
Away from traffic and the odors of agriculture and urban life, the smell of wood smoke was easily detectable.  The haze from fires almost 3,000 miles away made it appear to be an overcast day at Conewago Falls.
Due to the sudden cold, there were no insects flying above the Susquehanna during the first hour of daylight this morning, so swallows gathered in the trees to conserve energy until the hunt would be more productive.
The diabase boulders at Conewago Falls retain heat and provide an even better refuge from the cold than a dead tree on a chilly morning.  Here, a juvenile and an adult Tree Swallow (center) are surrounded by Northern Rough-winged Swallows.  Hundreds of each of these migratory species were feeding at the falls today.
Two dozen or more Barn Swallows, including this juvenile, were seen among the swarming birds.
Several late Bank Swallows, including this one (bottom center), were among the flocks of migrants at Conewago Falls this morning.  One Cliff Swallow (Petrochelidon pyrrhonota) was seen as well.
A Great Egret (Ardea alba) and a Great Blue Heron.
An Osprey searching the clear pools and rapids for a morning meal.
A juvenile Bald Eagle with the same goal in mind.
The same Bald Eagle keeping a close watch on the Osprey.  Bald Eagles frequently ambush Ospreys to steal their catch.  For a young eagle, acquiring the skill of fish theft may improve its chances of survival, at least until the Ospreys head south.

All that bright filtered sunlight was ideal for photographing butterflies along the Conewago Falls shoreline.  Have a look.

During the late morning, dozens of Monarch butterflies migrated past Conewago Falls.  This one paused to feed.
The Viceroy (Limenitis archippus) is a Monarch mimic.  Its appearance fools would-be predators into thinking it is a Monarch and possesses the same foul flavor as the milkweed-raised model.
This Variegated Fritillary (Euptoieta claudia) was among the late-season butterflies at Conewago Falls.
The Common Buckeye is presently just that, very common on flowers and moist sandy soil around the falls.
The Painted Lady is a regularly-occurring migratory species of butterfly.
The Red Admiral is typically a common to abundant migrant.  So far in 2020, they are scarce in the lower Susquehanna valley. 

A Visit to Second Mountain

If it can fly, there’s a pretty good chance it was at Second Mountain today.

What follows is a photographic chronology of some of today’s sightings at Second Mountain Hawk Watch at Fort Indiantown Gap in Lebanon County, Pennsylvania.  We begin with some of the hundreds of migratory songbirds found at the base of the mountain along Cold Spring Road near Indiantown Run during the early morning, then we continue to the lookout for the balance of the day.

A Black-and-white Warbler (Mniotilta varia) searching the trunk of a tree for insects.
A Rose-breasted Grosbeak.
A Blackburnian Warbler high in the forest canopy.
A Black-throated Green Warbler bouncing from branch to branch as it feeds.
A Chestnut-sided Warbler lurks among the foliage.
A Magnolia Warbler.
One of a hundred or more Red-eyed Vireos found swarming the treetops, and occasionally the understory, while engaging in a wild feeding frenzy.
A male American Redstart.  Judging by that gray hood, it’s probably experiencing its second fall migration.
Eyes were skyward at the Second Mountain Hawk Watch lookout as Broad-winged Hawks began streaming through during the mid-morning.
During the morning flight, Broad-winged Hawks including this adult floated by the lookout riding updrafts created by the south wind striking the face of the mountain ridge.
As the overcast became more scattered and more sunlight reached the ground, Broad-winged Hawks began riding thermal currents to gain altitude before gliding off to the southwest in continuance of their long trip to the tropics.  At times, birds would disappear into the base of the clouds before ending their climb and sailing away.
Broad-winged Hawks rely principally upon amphibians and large insects like this bush katydid (Scudderia species) for sustenance.  With freezing temperatures just around the corner, “broad-wings” must make their way to warmer climes early or risk starvation.
A Bald Eagle always gets observers looking.
A juvenile Broad-winged Hawk.
A juvenile Cooper’s Hawk.
A Broad-winged Hawk has a look around.
One never quite knows what one may see when having a look around.
A Cape May Warbler (Setophaga tigrina) in the lookout hemlock.
A Black Saddlebags, one of several migratory dragonflies seen today.
An Osprey glides through in the afternoon glare.
A speedy Merlin thrilled observers with a close approach.
One must remember that Fort Indiantown Gap is an active military installation, so from time to time training and drilling exercises may interrupt bird observation activities at the Second Mountain Hawk Watch.
Today, speedy A-10 Warthog attack aircraft piloted by members of the Maryland Air National Guard based at Glenn Martin Field thrilled observers on the lookout with several close passes during their training runs.
And repeat.
Drill complete.

The total number of Broad-winged Hawks observed migrating past the Second Mountain lookout today was 619.  To see the daily raptor counts for Second Mountain and other hawk watches in North America, and to learn more about each site, be sure to visit hawkcount.org

Big Fallout

Okay, so it happened to be cloudy with drizzle at sunrise—not the best conditions for observing birds in the treetops.  But that inclement weather effectively grounded the overnight flight of migrating songbirds leading to a really big fallout in the lower Susquehanna valley this morning.

While straining one’s neck to gaze up into the forest canopy, hundreds of migrants including warblers, vireos, tanagers, thrushes, and flycatchers could be seen.  Identifying each was impossible.

Here are of few of this morning’s arrivals.  Manually setting the camera to a slower shutter speed compensated a little bit for the backlighting caused by cloudy conditions.

Pine Warbler (Setophaga pinus).
Bay-breasted Warbler.
Black-throated Green Warbler.
Nashville Warbler (Leiothlypis ruficapilla).
Northern Parula (Setophaga americana).

Peak numbers of Broad-winged Hawks will pass through the area during the coming two weeks.  They most often migrate in groups, with sizes ranging from several individuals to hundreds or even thousands of birds.  Despite this being a less than ideal day for riding thermals and gliding off towards the southwest to continue their journey to the tropics, some “broad-wings” ventured aloft and were on their way soon after the drizzle subsided during mid-morning.

A Broad-winged Hawk lifts off from the cover of the forest where it spent the night.
The same Broad-winged Hawk (bottom) and an adult Bald Eagle gain altitude on a thermal updraft before the former glides away toward the southwest.

Bird Migration Highlights

The southbound bird migration of 2020 is well underway.  With passage of a cold front coming within the next 48 hours, the days ahead should provide an abundance of viewing opportunities.

Here are some of the species moving through the lower Susquehanna valley right now.

Blue-winged Teal are among the earliest of the waterfowl to begin southward migration.
Sandpipers and plovers have been on the move since July.  The bird in the foreground with these Killdeer is not one of their offspring, but rather a Semipalmated Plover (Charadrius semipalmatus), a regular late-summer migrant in the Lower Susquehanna River Watershed.
Hawk watch sites all over North America are counting birds right now.  The Osprey is an early-season delight as it glides past the lookouts.  Look for them moving down the Susquehanna as well.
Bald Eagles will be on the move through December.  To see these huge raptors in numbers, visit a hawk watch on a day following passage of a cold front when northwest winds are gusting.
Merlins were seen during this past week in areas with good concentrations of dragonflies.  This particular one at Middle Creek Wildlife Management Area in Lancaster and Lebanon Counties…
…was soon visited by another.
Check the forest canopy for Yellow-billed Cuckoos.  Some local birds are still on breeding territories while others from farther north are beginning to move through.
Ruby-throated Hummingbirds are darting through the lower Susquehanna valley on their way to the tropics.  This one has no trouble keeping pace with a passing Tree Swallow.
Nocturnal flights can bring new songbirds to good habitat each morning.  It’s the best time of year to see numbers of Empidonax flycatchers.  But, because they’re often silent during fall migration, it’s not the best time of year to easily identify them.  This one lacking a prominent eye ring is a Willow Flycatcher (Empidonax traillii).
During the past two weeks, Red-eyed Vireos have been numerous in many Susquehanna valley woodlands.  Many are migrants while others are breeding pairs tending late-season broods.
During mornings that follow heavy overnight flights, Blackburnian Warblers have been common among waves of feeding songbirds.
Chestnut-sided Warblers are regular among flocks of nocturnal migrants seen foraging among foliage at sunrise.
Scarlet Tanagers, minus the brilliant red breeding plumage of the males, are on their way back to the tropics for winter.
While passing overhead on their way south, Bobolinks can be seen or heard from almost anywhere in the lower Susquehanna valley.  Their movements peak in late August and early September.
During recent evenings, Bobolinks have been gathering by the hundreds in fields of warm-season grasses at Middle Creek Wildlife Management Area.
If you go to see the Bobolinks there, visit Stop 3 on the tour route late in the afternoon and listen for their call.  You’ll soon notice their wings glistening in the light of the setting sun as they take short flights from point to point while they feed.  Note the abundance of flying insects above the Big Bluestem and Indiangrass in this image.  Grasslands like these are essential habitats for many of our least common resident and migratory birds.

How Much Can a Bald Eagle Lift?

Here it is—just as it happened, recently in the lower Susquehanna valley.

A Bald Eagle in search of a meal.
The eagle glides in and grabs an unsuspecting Common Carp, the bird’s momentum and a head wind helping it to raise the fish out of the water.  This particular carp appears to be eighteen to twenty-four inches in length.  In that range, it could weigh anywhere from four to ten pounds or more.
But as the eagle tries to flap its wings to carry the carp skyward, it loses lift, and the weight of the fish drags the raptor down.  A carp exceeding twenty inches in length usually weighs more than five pounds, approximately half the mass of a male (about 9 lbs.) or a female (about 12 lbs.) Bald Eagle.  From a dead stop, trying to extricate a submerged fish weighing half as much again as it does is an impossible task for this or any other Bald Eagle.
The eagle fights briefly to pull the carp from the water, then abandons the effort to instead release its talons from the fish to prevent its own demise by drowning.
Free of its hold on the carp, the eagle flaps its wings briskly to get up and out of the potentially deadly situation.
Success!
Both the eagle and, presumably, the carp survive the encounter.
The eagle finds a nearby tree limb where it takes a much-needed break from fishing.
Such an event may have been fatal to an inexperienced younger Bald Eagle.  Though not an adult, this bird is no spring chicken.  Its plumage, particularly its white head with a dark line through the eye (often called an “osprey face”), is indicative of a bird in its fourth year of life.  By this time next year, it should be sporting a full set of adult feathers.  In the meantime, it should stick to eating suckers; there are plenty of those to go around.
Common Carp are classified as a minnow (Cyprinidae).  They are indigenous to Europe and are raised as a food fish in many parts of the world.  In the Lower Susquehanna River Watershed, Common Carp are an introduced species with negative impacts on native fisheries.  Those exceeding twenty inches in length begin to gain girth and weight, sometimes reaching thirty pounds at thirty inches.

SOURCES

Sedaghat, Safoura, Seyed Abbas Hoseini, Mohammad Larijani, and Khadijeh Shamekhi Ranjbar.  2013.  “Age and Growth of Common Carp (Cyprinus carpio Linnaeus, 1758) in Southern Caspian Sea, Iran”.  World Journal of Fish and Marine Sciences.  5:1.  pp.71-73.

Spotted Lanternfly in the Lower Susquehanna River Watershed

Second Mountain Hawk Watch is located on a ridge top along the northern edge of the Fort Indiantown Gap Military Reservation and the southern edge of State Game Lands 211 in Lebanon County, Pennsylvania.  The valley on the north side of the ridge, also known as St. Anthony’s Wilderness, is drained to the Susquehanna by Stony Creek.  The valley to the south is drained toward the river by Indiantown Run, a tributary of Swatara Creek.

The hawk watch is able to operate at this prime location for observing the autumn migration of birds, butterflies, dragonflies, and bats through the courtesy of the Pennsylvania Game Commission and the Garrison Commander at Fort Indiantown Gap.  The Second Mountain Hawk Watch Association is a non-profit organization that staffs the count site daily throughout the season and reports data to the North American Hawk Watch Association (posted daily at hawkcount.org).

Today, Second Mountain Hawk Watch was populated by observers who enjoyed today’s break in the rainy weather with a visit to the lookout to see what birds might be on the move.  All were anxiously awaiting a big flight of Broad-winged Hawks, a forest-dwelling Neotropical species that often travels back to its wintering grounds in groups exceeding one hundred birds.  Each autumn, many inland hawk watches in the northeast experience at least one day in mid-September with a Broad-winged Hawk count exceeding 1,000 birds.  They are an early-season migrant and today’s southeast winds ahead of the remnants of Hurricane Florence (currently in the Carolinas) could push southwest-heading “Broad-wings” out of the Piedmont Province and into the Ridge and Valley Province for a pass by the Second Mountain lookout.

The flight turned out to be steady through the day with over three hundred Broad-winged Hawks sighted.  The largest group consisted of several dozen birds.  We would hope there are probably many more yet to come after the Florence rains pass through the northeast and out to sea by mid-week.  Also seen today were Bald Eagles, Ospreys, American Kestrels, and a migrating Red-headed Woodpecker.

Migrating Broad-winged Hawks circle on a thermal updraft above Second Mountain Hawk Watch to gain altitude before gliding away to the southwest.

Migrating insects included Monarch butterflies, and the three commonest species of migratory dragonflies: Wandering Glider, Black Saddlebags, and Common Green Darner.  The Common Green Darners swarmed the lookout by the dozens late in the afternoon and attracted a couple of American Kestrels, which had apparently set down from a day of migration.  American Kestrels and Broad-winged Hawks feed upon dragonflies and often migrate in tandem with them for at least a portion of their journey.

Still later, as the last of the Broad-winged Hawks descended from great heights and began passing by just above the trees looking for a place to settle down, a most unwelcome visitor arrived at the lookout.  It glided in from the St. Anthony’s Wilderness side of the ridge on showy crimson-red wings, then became nearly indiscernible from gray tree bark when it landed on a limb.  It was the dreaded and potentially invasive Spotted Lanternfly (Lycorma delicatula).  This large leafhopper is native to Asia and was first discovered in North America in the Oley Valley of eastern Berks County, Pennsylvania in 2014.  The larval stage is exceptionally damaging to cultivated grape and orchard crops.  It poses a threat to forest trees as well.  Despite efforts to contain the species through quarantine and other methods, it’s obviously spreading quickly.  Here on the Second Mountain lookout, we know that wind has a huge influence on the movement of birds and insects.  The east and southeast winds we’ve experienced for nearly a week may be carrying Spotted Lanternflies well out of their most recent range and into the forests of the Ridge and Valley Province.  We do know for certain that the Spotted Lanternfly has found its way into the Lower Susquehanna River Watershed.

This adult Spotted Lanternfly landed in a birch tree behind the observers at the Second Mountain Hawk Watch late this afternoon.  It was first recognized by its bright red wings as it glided from treetops on the north side of the lookout.

A Flock of Seagulls?

At the moment there is a heavy snow falling, not an unusual occurrence for mid-February, nevertheless, it is a change in weather.  Forty-eight hours ago we were in the midst of a steady rain and temperatures were in the sixties.  The snow and ice had melted away and a touch of spring was in the air.

Big Bluestem in the Riverine Grasslands is inundated by the rising waters of the Susquehanna at Conewago Falls.   The river ice has been dispersed by the recent mild temperatures and rains.

Anyone casually looking about while outdoors during these last several days may have noticed that birds are indeed beginning to migrate north in the lower Susquehanna valley.  Killdeer, American Robins, Eastern Bluebirds, Red-winged Blackbirds, and Common Grackles are easily seen or heard in most of the area now.

Just hours ago, between nine o’clock this morning and one o’clock this afternoon, there was a spectacular flight of birds following the river north, their spring migration well underway.  In the blue skies above Conewago Falls, a steady parade of Ring-billed Gulls was utilizing thermals and riding a tailwind from the south-southeast to cruise high overhead on a course toward their breeding range.

Ring-billed Gulls swarm in a thermal updraft above Conewago Falls to gain altitude prior to streaming off to the north and continuing their journey.
Ring-billed Gulls climbing to heights sometimes exceeding 1,000 feet before breaking off and gliding away to the north.

The swirling hoards of Ring-billed Gulls attracted other migrants to take advantage of the thermals and glide paths on the breeze.  Right among them were 44 Herring Gulls, 3 Great Black-backed Gulls, 12 Tundra Swans (Cygnus columbianus), 10 Canada Geese, 3 Northern Pintails (Anas acuta), 6 Common Mergansers, 3 Red-tailed Hawks, a Red-shouldered Hawk, 6 Bald Eagles (non-adults), 8 Black Vultures, and 5 Turkey Vultures.

A first-year Herring Gull (top center) is a standout in a “kettle” of Ring-billed Gulls.
How many Ring-billed Gulls passed by today?  More than 18,000…with emphasis on MORE THAN.  You see, early this afternoon, the handy-dandy clicker-counter used to tick off and tally the big flights of birds as they pass by quit clicking and counting.  Therefore, 18,000 is the absolute minimum number of Ring-billed Gulls seen migrating north today.  Hopefully the trusty old oil can will get the clicker working again soon.

In the afternoon, the clouds closed in quickly, the flight ended, and by dusk more than an inch of snow was on the ground.  Looks like spring to me.

Migrating North?

CLICK ON THE LOGO FOR TODAY’S MIGRATION COUNT TOTALS

A steady stream of birds was on the move this morning over Conewago Falls.  There were hundreds of Ring-billed Gulls, scores of Herring Gulls, and a few Great Black-backed Gulls to dominate the flight.  Then too there were thirteen Mallards, Turkey Vultures and a Black Vulture, twenty or more American Robins, a half a dozen Bald Eagles (juvenile and immature birds), a couple of Red-winged Blackbirds, and, perhaps most unusual of all, a flock of a dozen Scoters (Melanitta species), a waterfowl typical of the Mid-Atlantic surf in winter.  All of these birds were diligently following the river, and into a headwind no less.

“Hold on just a minute there, buster,” you may say, “I’ve looked at the migration count by dutifully clicking on the logo above and there is nothing but zeroes on the count sheet for today.  The season totals have not changed since the previous count day!”

Ah-ha, my dedicated friend, correct you are.  It seems that today’s bird flight was solely in one direction.  And that direction was upriver, moving north into a north breeze, on a heading which conflicts with all logic for creatures that should still be headed south for winter.  As a result, none of the birds observed today were counted on the “Autumn Migration Count”.

You might say, “Don’t you know that Winter Solstice was three days ago, so autumn and autumn migration is over.”

Okay, point well taken.  I should therefore clarify that what we title as “Autumn Migration Count” is more accurately a census of birds, insects, and other creatures transiting from northerly latitudes to more favorable latitudes to the south for winter.  This transit can begin as early as late June and extend into the first weeks of winter.  While most of this movement is motivated by the reduced hours of daylight during the period, late season migrants are often responding to ice, bad weather, or lack of food to prompt a journey further south.  Migration south in late December and January occurs even while the amount of daylight is increasing slightly in the days following the Winter Solstice.

So what of the birds seen flying north today?  There was some snow cover that has melted away, and the ice that formed on the river a week ago is gone due to the milder than normal temperatures this week.

One may ask, “Were the birds seen today migrating north?”

Let’s look at the species seen moving upriver today a try to determine their motivation.

First, and perhaps most straight-forward, is the huge flight of gulls.  Wintering gulls on the Susquehanna River near Conewago Falls tend to spend their nights in flocks on the water or on treeless islands and rocky outcrops in the river.  Many hundreds, sometimes thousands, find such favorable sites along the fifteen mile stretch of river from Conewago Falls downstream to Lake Clarke and the Conejohela Flats at Washington Boro.  Each morning most of these gulls venture out to suburbia, farmland, landfill, hydroelectric dams, and other sections of river in search of food.  Gulls are very able fliers and easily cover dozens of miles outbound and inbound each day in search of food.  Many of the gulls seen this morning were probably on their way to the Harrisburg metropolitan area to eat trash.  Barring any extraordinary buildups of ice on this section of river, one would expect these gulls to remain and make these daily excursions to food sources through early spring.

Ring-billed Gulls fly upriver through the Pothole Rocks at Conewago Falls.
Herring Gulls stream upriver through Conewago Falls on their way to fine dining.

Second, throughout the season Bald Eagles have been tallied on the migration count with caution.  Flight altitude, behavior, plumage, and the reaction of the “local” eagles to these transients was carefully considered before counting an eagle as a migrant.  They roam a lot, particularly when young, and range widely to feed.  The movement of eagles up the river today was probably food related.  A gathering of adult, juvenile, and immature Bald Eagles could be seen more than a half mile upstream from the migration count lookout.  Those moving up the river seemed to assemble with the “locals” there throughout the morning.  White-tailed Deities occasionally drown, particularly when there is thin or unstable ice on the river (as there was last week) and they attempt to tread upon it.  Then, their bodies are often stranded among rocks, in trees, or on the crown of the dam.  After such a mishap, their carcasses become meals for carrion-eaters in the falls.  Such an unfortunate deity, or another source of food, may have been attracting the eagles in numbers today.

A distant gathering of Bald Eagles at the south end of Three Mile Island in upper Conewago Falls.

Next, Black and Turkey Vultures often roam widely in search of food.  The small numbers seen headed up-river today would tend to mean very little when trying to determine if there is a trend or population shift.  Again, food may have been luring them upriver from nearby roosts.

And finally, the scoters, Mallards, American Robins, and Red-winged Blackbirds may have been wandering as well.  Toward mid-day, the wind speed picked up and the direction changed to the east.  This raises the possibility that these and others of the birds seen today may sense a change in weather, and may seek to take flight from the inclement conditions.  Prompted by the ocean breeze and in an attempt to avoid a storm, was there some movement away from the Atlantic Coastal Plain to the upper Piedmont today?  Many species may make these types of reactive movements.  Is it possible that some birds flee or avoid ever-changing storm tracks and alter there wintering locations based on jet streams, water currents, and other climatic conditions?  Probably.  These are interesting dynamics and something worthy of study outside the simpler methods of a migration count.

A Ring-billed Gull begins feeding as storm clouds approach Conewago Falls at mid-day.  This and other gull species travel widely in their winter range to find food and safe roosting sites.  For them, northward spring migration usually begins no earlier than late February.