An Encore of the Susquehanna Seawatch

In late March and early April, a rainy night and fog at daybreak can lead to an ideal morning for spotting migratory waterfowl and seabirds during their layover on the lower Susquehanna.  Visibility was just good enough to spot these birds at Harrisburg, Pennsylvania, most of them feeding at midriver.

Northern Shovelers are regular migrants, more often seen on ponds and in wetlands than on the river.
A pair of American Wigeons head upriver.
A Horned Grebe.
A small flock of northbound Buffleheads.
Ring-necked Ducks.
Lesser Scaup, eight of the more than 100 seen along Front Street in Harrisburg at the Pennsylvania Governor’s Residence.  Note how the white bar on the wing’s secondaries becomes diffused and dusky in the primaries.
Lesser Scaup spend the winter on bays and lakes to our south.
More Scaup, the lead bird with bright white extending through the secondaries into the primaries is possibly a Greater Scaup (Aythya marila).
Long-tailed Ducks, formerly known as Oldsquaw, are a diving duck that winters on the Great Lakes and on bays along the Atlantic Coast.  They nest on freshwater ponds and lakes in the tundra of Canada and Alaska.
A male Common Merganser.
This pair of Hooded Mergansers may be nesting in a tree cavity nearby.
The local Peregrine Falcon grabbed a passing Common Grackle…
…prompting the more than 100 Bonaparte’s Gulls in the vicinity to quickly depart and fly upstream.
Birds of Conewago Falls in the Lower Susquehanna River Watershed: Northern Flicker
It pays to keep an eye on the trees along the shoreline too.  Migrants like this Northern Flicker are beginning to come through in numbers.

A Tufted Duck at Middle Creek

With large crowds of observers stopping by at the Pennsylvania Game Commission’s Middle Creek Wildlife Management Area to view the thousands of migrating Snow Geese and Tundra Swans there, you may not notice the smaller but just as enthusiastic crowd gathering at the refuge to see a single, rather inconspicuous waterfowl, a male Tufted Duck (Aythya fuligula).  This extraordinarily rare visitor has been on the refuge for at least two weeks now.  The Tufted Duck, a diving benthic feeder, is native to Europe and Asia, but this vagrant individual seems to be comfortable in the company of its North American counterparts, a flock of Ring-necked Ducks.  Birders known as “listers” relish the chance to see such an unusual find.  Many are traveling from bordering states for a chance to add it to their list of species observed during their lifetime—their “life list”.

Birds/Waterfowl of Conewago Falls in the Lower Susquehanna River Watershed: Tufted Duck
The male Tufted Duck (right) with a male Ring-necked Duck (left).
Birds/Waterfowl of Conewago Falls in the Lower Susquehanna River Watershed: Tufted Duck
This male Tufted Duck has been seen in the company of Ring-necked Ducks and other waterfowl on this pond located opposite the small white shed along Hopeland Road in the Lebanon County section of the Middle Creek W.M.A.  It has also been seen on other nearby ponds and, when the Hopeland Road pond is frozen, on the main lake near Willow Point.
Birds/Waterfowl of Conewago Falls in the Lower Susquehanna River Watershed: Tufted Duck
A Canada Goose, an American Wigeon, and the rare Tufted Duck.  If you want to see the Tufted Duck’s “tuft”, you’ll need to remember your binoculars or, better yet, a spotting scope.

Want to start a “life list” of bird sightings?  Just get out a piece of paper or start a document on your computer and jot down the name of the bird and the date and location where you saw it for the first time.  That’s all there is to it.  Beginning a “life list” can be the start of a lifelong passion.  And a Tufted Duck wouldn’t be too shabby as the first “lifer” on your list.

Snow Goose Numbers Peaking

It’s that time—Snow Goose numbers are peaking at Middle Creek Wildlife Management Area in Lancaster/Lebanon Counties.

Today, migrating Snow Geese arriving from wintering areas on the Atlantic Coastal Plain blanketed the ice-free half of the lake at Middle Creek.  There are probably in excess of 100,000 birds at the refuge right now.
The density on the lake is relieved as geese filter out to a nearby field to graze.
Periodically throughout the day, observers are thrilled by the sight of Snow Geese rising into the air in unison as a thunderously loud cloud of birds.
Open water is at a premium right now, so these Ring-necked Ducks and a Tundra Swan have to squeeze in where they can.
If you’re going to Middle Creek to see the Snow Geese, be certain to bring your camera and viewing optics.  If you want to miss the largest crowds, the Pennsylvania Game Commission recommends visiting during the morning or on a weekday.  For everyone’s safety, please remember to slow down and follow the posted parking directives.  And so that the wildlife isn’t disturbed by your visit, please heed the signs designating the no-entry and propagation zones.

Snow Geese Arriving

With plenty of open water on the main lake and no snow cover on the fields where they graze, Snow Geese have begun arriving at Middle Creek Wildlife Management Area in Lancaster/Lebanon Counties.  As long as our mild winter weather continues, more can be expected to begin moving inland from coastal areas to prepare for their spring migration and a return to arctic breeding grounds.

You probably need a break from being indoors all month, so why not get out and have a look?

Hundreds of high-flying Snow Geese descended onto the main lake at Middle Creek Wildlife Management Area this afternoon.
Snow Geese and a few Ring-necked Ducks as seen from the Willow Point observation area at Middle Creek this afternoon.
The sound of calling Tundra Swans is music to the ears on an otherwise quiet winter day.
Dozens of Common Mergansers are at Middle Creek W.M.A. right now.
Look carefully and you might see American Black Ducks among the waterfowl in the refuge’s impoundments.
Northern Shovelers have been at Middle Creek since late fall.  If they can continue to access the muddy bottom of the refuge’s lake for food, they’ll stay until the spring migration.
Check those flocks of Canada Geese carefully, sometimes you’ll find something different among them,…
…like this noticeably smaller bird, probably either a Lesser Canada Goose (Branta canadensis parvipes) or a Richardson’s Cackling Goose (Branta hutchinsii hutchinsii).

Don’t just sit there—don your coat, grab a pair of binoculars, and get out and have a gander!

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.

The Fallout Continues

Fog and mist lingered throughout the day, as did the migratory water birds on the river and lakes in the lower Susquehanna valley.  As a continuation of yesterday’s post on the fallout, here’s a photo tour of some of the sites where ducks, loons, grebes, and other birds have gathered.

American Robins may have comprised a large portion of the northbound flight appearing on last evening’s radar images.  Today, hundreds could be seen on soggy lawns where earthworms might be found near the surface.  This flock was finding sustenance at Highspire’s Reservoir Park in Dauphin County.
This drake Gadwall (Mareca strepera) and two hens had dropped in for a visit at the Highspire Reservoir Park.
Hundreds of Buffleheads were on the fogged-in Susquehanna River at Harrisburg this afternoon.  From Front Street and Maclay Street in front of the Pennsylvania Governor’s Mansion, they seemed to be everywhere in sight on the rain-swollen current.  After passing downstream, flocks flew in a straight line formation just above the water’s surface as they made a short trip back up the river to then drift down through the channels once again.
A portion of a raft consisting of about three dozen Red-breasted Mergansers floats by the Pennsylvania Governor’s Mansion.  Several of the hundred or more Scaup on the river intermingled with these mergansers from time to time.
A lone Long-tailed Duck (Clanqula hyemalis) near the aforementioned raft of mergansers.  The Long-tailed Duck was formerly known as the Oldsquaw in North America.  The common name used in Britain and Europe is now preferred.
Two of at least a hundred Horned Grebes (Podiceps auritus) seen in the Susquehanna at Harrisburg this afternoon.
American Coots (Fulica americana) at Memorial Lake State Park in Lebanon County.
Buffleheads continue at Memorial Lake.
One more Common Loon than yesterday at Memorial Lake.
A mixed raft of diving ducks and grebes at Memorial Lake.
A closeup of the same raft reveals Buffleheads, Scaup, Ring-necked Ducks, Ruddy Ducks (Oxyura jamaicensis), a Pied-billed Grebe, and Horned Grebes.

Stormy weather certainly is a birder’s delight.

A Springtime Quiz

The mild winter has apparently minimized weather-related mortality for the local Green Frog population.  With temperatures in the seventies throughout the lower Susquehanna valley for this first full day of spring, many recently emerged adults could be seen and, on occasion, heard.  Yellow-throated males tested their mating calls—reminding the listener of the sound made by the plucking of a loose banjo string.

Here’s a gathering of Green Frogs seen this afternoon along the edge of a small pond.  How many can you find in this photograph?

If you venture out, keep alert for the migrating birds of late winter and early spring.

Yellow-bellied Sapsuckers are moving through on their way north.  Look for them in mature trees in woodlands, suburbs, and city parks.
The Fox Sparrow (Passerella iliaca), our largest sparrow, is a thrush-like denizen of shrubby forest understories and field edges.  It is an early spring and late autumn transient in the lower Susquehanna valley.
While stopping to rest and feed during their northbound spring journey, Ring-necked Ducks and other diving duck species visit wetlands and flooded timber along the Susquehanna River as well as clear ponds and lakes elsewhere in the watershed.
Eastern Bluebirds are presently migrating through the area.  Some will stay to breed where nest boxes or natural cavities are available in suitable habitat.
Tree Swallows are now arriving.  In open grasslands, pastures, and adjacent to almost any body of water, they will nest in boxes like those placed for bluebirds.
Keep that bird bath clean and fill it with fresh water, the American Robin flights are peaking right now.  Breeding males like this one are starting to sing and defend nesting territories.
Red-winged Blackbirds, like other native blackbirds, are moving through in a fraction of the numbers that were seen in the lower Susquehanna valley during the latter decades of the twentieth century.  They remain a common breeding species in pastures and cattail wetlands.
And of course, keep an eye to the sky.  There are still thousands of Snow Geese in the area.

If you’re staying close to home, be sure to check out the changing appearance of the birds you see nearby.  Some species are losing their drab winter basic plumage and attaining a more colorful summer breeding alternate plumage.

European Starlings are losing their spotted winter (basic) plumage and beginning to display a glossy multicolored set of breeding feathers.
An American Goldfinch in transition from winter (basic) plumage to bright yellow, black, and white summer colors.

So just how many Green Frogs were there in that first photograph?  Here’s the answer.

If you counted seven, you did really well.  Numbers eight and nine are very difficult to discern.

Happy Spring.  For the benefit of everyone’s health, let’s hope that it’s a hot and humid one!

It is the First Full Day of Spring…Isn’t It?

You remember the signs of an early spring, don’t you?  It was a mild, almost balmy, February.  The earliest of the spring migrants such as robins and blackbirds were moving north through the Lower Susquehanna River Watershed.  The snow had melted and ice on the river had passed.  Everyone was outdoors once again.  At last, winter was over and only the warmer months lie ahead…beginning with March.

Common Grackles are often the first perching birds to begin moving north through the lower Susquehanna valley in spring.  They often winter in large roving flocks of mixed blackbird species on the nearby Atlantic Coastal Plain Province.  These flocks sometimes wander the farmlands of the lower Piedmont Province near the river, but rarely stray north of the 40th parallel before February.

Ah yes, March, the cold windy month of March.  We remember February fondly, but this March has startled us out of our vernal daydreams to wrestle with the reality of the season.  And if you’re anywhere near the Mid-Atlantic states on this first full day of spring, you know that a long winter’s nap and visions of sugar peas would be time better spent than a stroll outdoors.  Presently it’s dusk, and the snow from the 4th “Nor’easter” in a month is a foot deep and still falling.

In honor of “The Spring That Was”, here then is a sampling of some of the migratory waterfowl that have found their way to the Lower Susquehanna River Watershed during March.  Some are probably lingering and feeding for a while.  All will move along to their breeding grounds within a couple of weeks, regardless of the weather.

Tundra Swans will migrate in a northwest direction to reach breeding grounds west and north of Hudson Bay.
Migratory Canada Geese departing the Chesapeake Bay area typically pass over the lower Susquehanna valley at high altitudes.  A south wind can bring a sustained day-long flight of migrating geese and ducks over the region on a given day in late-February or March.
Snow Geese (Chen caerulescens) historically wintered in the marshes of the Atlantic seaboard where the tide cycle kept vegetation primarily snow-free for feeding.  Removal of hedgerows and intensive farming since the 1980s has attracted these birds to inland agricultural lands during their preparation for the move north.  For nearly three decades, tens of thousands have annually begun their spring journey with a stopover at the Middle Creek Wildlife Management Area.  Flocks range widely from Middle Creek to feed, commonly as far west as the fields of the Conewago Creek valley in the Gettysburg Basin to the east of Conewago Falls.  
American Black Ducks
A pair of Northern Shovelers (Anas clypeata).
Ring-necked Ducks (Aythya collaris) are “diving ducks”.
A male Lesser Scaup, Aythya affinis, (front center) and Ring-necked Ducks (rear and left) seen between feeding dives.
A male Bufflehead (Bucephala albeola).  These miniature diving ducks will sometimes winter on the Susquehanna in “rafts” of dozens of birds.
Tundra Swans journey toward the “Land of the Mid-Night Sun”.