Osprey – LIFE IN THE LOWER SUSQUEHANNA RIVER WATERSHED

October 5, 2024October 6, 2024

A Sunny Day to Get Things Moving Again

At last, the bird migration is picking up where it left off after the third week of September when rain, fog, and gloom arrived for a two week stay in the lower Susquehanna valley. Now that this persistent meteorological interluder has departed the stage, our stalled avians can resume the autumn spectacle.

There are still a few Barn Swallows around. By October, they’ve usually departed for more southern climes. Our more common late-season species are the Tree and Northern Rough-winged Swallows, both of which tend to be found close to water and are thus able to still grab flying insects on mornings when the air temperature over land is too cold for their favored prey. We found this Barn Swallow following the lead of its cool-weather counterparts, hawking up its breakfast over a warm sun-drenched pond.

While the vast majority of the Neotropical flycatchers are now gone for the year, Eastern Phoebes are currently moving through in large numbers. Like the late-season swallows, these insectivores are a temperate species with an affinity for habitats near water.

Though getting harder to find, there are still some Neotropical warblers moving through. This Black-throated Green Warbler was strongly outnumbered by the Ruby-crowned Kinglets in a mixed flock of woodland songbirds.

A Northern Parula in the mixed flock of migrants.

One of dozens of Ruby-crowned Kinglets encountered this morning.

Despite the inclement weather, diurnal flights of southbound Blue Jays have continued throughout the past week.

Migrating Blue Jays are best seen during the first few hours after sunrise.

Red-bellied Woodpeckers, after extending their range north through the Susquehanna watershed and beyond during the past century, have now become a regular fall migrant as they withdraw from the northernmost periphery of their breeding grounds. This individual was photographed while taking a break from its diurnal flight and was one of more than three dozen seen at Second Mountain Hawk Watch on Thursday, October 3.

After a significant delay, especially for the Neotropical Broad-winged Hawks, diurnal raptor flights have resumed. Now is the time to see the widest variety of species, including migrants like this Osprey, at any one of the regional hawk-counting stations.

Numbers of migrating Sharp-shinned Hawks are now reaching their seasonal peak. Be certain to check out “Hawkwatchers Helper: Identifying Bald Eagles and Other Diurnal Raptors” by clicking the tab at the top of this page. There you’ll find a listing of regional lookouts and a photo guide to help you identify the species you see.

August 26, 2024September 13, 2024

Southbound Flights: On Their Way Both Night and Day

It’s hard to believe, but for almost two months now, sandpipers, plovers, and terns have been filtering south through the Lower Susquehanna River Watershed on their way to the Atlantic coastline as they complete the first leg of their long autumn migration—a journey that will take some species all the way to the far reaches of the South American continent for winter.

Caspian Terns and Osprey — Migrating Caspian Terns and an Osprey take a break on a lower Susquehanna valley gravel bar.

As August draws to a close, these early birds are being joined by widespread nocturnal flights of Neotropical migrants—those species, primarily songbirds, on their way to wintering grounds which lie exclusively south of the continental United States.

To catch a glimpse of these night-flying avians, your best bet may be to position yourself on the crest of a ridge or along a linear break in the forest such as a utility right-of-way where waves of warblers, vireos, flycatchers, and other Neotropical passerines sometimes feed on invertebrates after making landfall at daybreak. Pick a place where the trees are bathed in the warm light of the rising sun and be there by 7 A.M. E.D.T. The activity can be tremendous, but it usually ends between 8 and 9.

One of more than half a dozen Red-eyed Vireos seen during a daybreak fallout at Second Mountain Hawkwatch in Lebanon County earlier this week.

During sunrise, a just-arrived Blackburnian Warbler checks the foliage of a ridgetop Red Maple for insects.

A Least Flycatcher quietly searches the shrubby growth along the forest edge for a morning meal.

A Black-and-white Warbler in the first hour of sunlight after a big nocturnal flight.

A Scarlet Tanager having a look around. This individual and other migrating birds may be here for a few days before moving on.

A hungry Chestnut-sided Warbler inspects limbs, leaves, and twigs looking for nourishment after an all-night flight.

Diurnal migrants, birds that make their movements during the daylight hours, are ramping up their flights now as well. Broad-winged Hawks, Bald Eagles, and falcons are currently being tallied at hawk-counting stations throughout the northeast. Many of those lookouts are seeing Ruby-throated Hummingbirds, swallows, and other daytime migrants too.

Many American Kestrels transit our area in August and early September, a time coinciding with flights of migratory dragonflies, insects upon which they and another falcon, the Merlin, frequently prey.

Chimney Swifts are fast-flying diurnal migrants. They are beginning to congregate into larger groups in preparation for their departure. Some are already on the move.

Cedar Waxwings are currently being seen in roving flocks throughout the region. Their migration is less of a point-to-point flight and more of a continuous wandering in search of berries and other wild foods.

Not everyone is yet ready to go. American Goldfinches are still in the midst of their nesting cycle and won’t begin leaving until the young are on their own and colorful adult males like this one are beginning to molt into their drab winter plumage.

Autumn migration flights are an ever-changing process, with different species peaking at different times throughout the season. In these months just after the nesting season, each of these species is more numerous than at any other time of the year. And of course, the more often we as observers get out and have a look, the more of them we’ll see.

Be certain to click the “Birds” tab at the top of this page for a photo guide to the species you’re likely to see passing through the lower Susquehanna valley this fall. Nearly four months of autumn hawk migration flights lie ahead, so don’t forget to click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab to find a hawk-counting station near you, then stop by for a visit or two. See you there!

Nocturnal Migrants at Liftoff — A large nightfall liftoff of nocturnal migrating birds is shown here on this evening’s State College, Pennsylvania, Doppler Radar base velocity loop. Returns indicating birds moving toward the radar site (the white dot in the center of the color mass) are shown in green, and those indicating birds moving away are indicated in red. This is a big flight headed generally in a south-southwest direction. (NOAA/National Weather Service Doppler Radar image)

October 13, 2023October 16, 2023

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.

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 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.

Bald Eagles are commonly seen at both coastal and inland lookouts. Their movements continue well into late fall.

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.

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.

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!

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.

August 28, 2023September 7, 2023

Shorebirds on the Mud in York County, Pennsylvania

At Lake Redman just to the south of York, Pennsylvania, a draw down to provide drinking water to the city while maintenance is being performed on the dam at neighboring Lake Williams, York’s primary water source, has fortuitously coincided with autumn shorebird migration. Here’s a sample of the numerous sandpipers and plovers seen today on the mudflats that have been exposed at the southeast end of the lake…

Least Sandpiper at Lake Redman, York County, Pennsylvania. — One of a hundred or more Least Sandpipers seen on mudflats at Lake Redman today.

A Semipalmated Plover and a Least Sandpiper at Lake Redman, York County, Pennsylvania. — A Semipalmated Plover and a Least Sandpiper

Pectoral Sandpipers at Lake Redman, York County, Pennsylvania. — Pectoral Sandpipers.

A Pectoral Sandpiper and Least Sandpipers at Lake Redman, York County, Pennsylvania. — A Pectoral Sandpiper and two Least Sandpipers.

A Semipalmated Sandpiper at Lake Redman, York County, Pennsylvania. — A Semipalmated Sandpiper.

A Stilt Sandpiper at Lake Redman, York County, Pennsylvania. — A Stilt Sandpiper feeding.

Stilt Sandpiper consuming an edible at Lake Redman, York County, Pennsylvania. — Stilt Sandpiper consuming an edible.

Stilt Sandpiper at rest at Lake Redman, York County, Pennsylvania. — Stilt Sandpiper at rest.

A Solitary Sandpiper at Lake Redman, York County, Pennsylvania. — A Solitary Sandpiper

A Lesser Yellowlegs at Lake Redman, York County, Pennsylvania. — A Lesser Yellowlegs.

A Greater Yellowlegs at Lake Redman, York County, Pennsylvania. — A Greater Yellowlegs.

Osprey at Lake Redman, York County, Pennsylvania. — Stirring up the shorebird crowd every now and then were several Ospreys, but all would soon be back to the business of feeding in the mud.

An Osprey hovers above shallow water near the mudflats as it searches for fish.

Not photographed but present at Lake Redman were at least two additional species of shorebirds, Killdeer and Spotted Sandpiper—bringing the day’s tally to ten. Not bad for an inland location! It’s clearly evident that these waders overfly the lower Susquehanna valley in great numbers during migration and are in urgent need of undisturbed habitat for making stopovers to feed and rest so that they might improve their chances of surviving the long journey ahead of them. Mud is indeed a much needed refuge.

July 24, 2023August 25, 2023

Shorebirds and More at Bombay Hook National Wildlife Refuge

Have you purchased your 2023-2024 Federal Duck Stamp? Nearly every penny of the 25 dollars you spend for a duck stamp goes toward habitat acquisition and improvements for waterfowl and the hundreds of other animal species that use wetlands for breeding, feeding, and as migration stopover points. Duck stamps aren’t just for hunters, purchasers get free admission to National Wildlife Refuges all over the United States. So do something good for conservation—stop by your local post office and get your Federal Duck Stamp.

2023-2024 Federal Duck Stamp. Your Federal Duck Stamp is your free pass to visit the nation's National Wildlife Refuges including Bombay Hook National Wildlife Refuge on Delaware Bay near Smyrna, Delaware. — Your Federal Duck Stamp is your admission ticket for entry into many of the country’s National Wildlife Refuges including Bombay Hook National Wildlife Refuge on Delaware Bay near Smyrna, Delaware.

Still not convinced that a Federal Duck Stamp is worth the money? Well then, follow along as we take a photo tour of Bombay Hook National Wildlife Refuge. Numbers of southbound shorebirds are on the rise in the refuge’s saltwater marshes and freshwater pools, so we timed a visit earlier this week to coincide with a late-morning high tide.

This pair of Northern Bobwhite, a species now extirpated from the Lower Susquehanna River Watershed and the rest of Pennsylvania, escorted us into the refuge. At Bombay Hook, they don’t waste your money mowing grass. Instead, a mosaic of warm-season grasses and early successional growth creates ideal habitat for Northern Bobwhite and other wildlife.

Shearness Pool at Bombay Hook N.W.R. — Twice each day, high tide inundates mudflats in the saltwater tidal marshes at Bombay Hook prompting shorebirds to move into the four man-made freshwater pools. Birds there can often be observed at close range. The auto tour route through the refuge primarily follows a path atop the dikes that create these freshwater pools. Morning light is best when viewing birds on the freshwater side of the road, late-afternoon light is best for observing birds on the tidal saltwater side.

A Great Blue Heron at high tide on the edge of a tidal creek that borders Bombay Hook’s tour route at Raymond Pool.

Semipalmated Sandpipers stream into Raymond Pool to escape the rising tide in the salt marsh.

Semipalmated Sandpipers and Short-billed Dowitcher — More Semipalmated Sandpipers and a single Short-billed Dowitcher (Limnodromus griseus) arrive at Raymond Pool.

Two more Short-billed Dowitchers on the way in.

Sandpipers, Avocets, Egrets, and Mallards — Recent rains have flooded some of the mudflats in Bombay Hook’s freshwater pools. During our visit, birds were often clustered in areas where bare ground was exposed or where water was shallow enough to feed. Here, Short-billed Dowitchers in the foreground wade in deeper water to probe the bottom while Semipalmated Sandpipers arrive to feed along the pool’s edge. Mallards, American Avocets, and egrets are gathered on the shore.

Semipalmated Sandpipers, Short-billed Dowitchers, and Forster's Terns — Hundreds of Semipalmated Sandpipers, several Short-billed Dowitchers, and some Forster’s Terns (Sterna forsteri) crowd onto a mud bar at Bear Swamp Pool.

Semipalmated Sandpipers, Forster's Terns, and a Short-billed Dowitcher — A zoomed-in view of the previous image showing a tightly packed crowd of Semipalmated Sandpipers, Forster’s Terns, and a Short-billed Dowitcher (upper left).

Short-billed Dowitchers, American Avocets, and a Snowy Egret in Raymond Pool. A single Stilt Sandpiper (Calidris himantopus) can been seen flying near the top of the flock of dowitchers just below the egret.

Stilt Sandpiper among Short-billed Dowitchers — Zoomed-in view of a Stilt Sandpiper (Calidris himantopus), the bird with white wing linings.

American Avocets probe the muddy bottom of Raymond Pool.

Dunlin and Short-billed Dowitchers — Among these Short-billed Dowitchers, the second bird from the bottom is a Dunlin. This sandpiper, still in breeding plumage, is a little bit early. Many migrating Dunlin linger at Bombay Hook into October and even November.

This Least Sandpiper found a nice little feeding area all to itself at Bear Swamp Pool.

A Greater Yellowlegs at Bear Swamp Pool.

Marsh Wren singing — The chattering notes of the Marsh Wren’s (Cistothorus palustris) song can be heard along the tour road wherever it borders tidal waters.

Marsh Wren Nest — This dome-shaped Marsh Wren nest is supported by the stems of Saltwater Cordgrass (Sporobolus alterniflorus), a plant also known as Smooth Cordgrass. High tide licks at the roots of the cordgrass supporting the temporary domicile.

By far the most common dragonfly at Bombay Hook is the Seaside Dragonlet (Erythrodiplax berenice). It is our only dragonfly able to breed in saltwater. Seaside Dragonlets are in constant view along the impoundment dikes in the refuge.

Red-winged Blackbirds are still nesting at Bombay Hook, probably tending a second brood.

Look up! A migrating Bobolink passes over the dike at Shearness Pool.

Mute Swans and Canada Geese — Non-native Mute Swans and resident-type Canada Geese in the rain-swollen Shearness Pool.

A pair of Trumpeter Swans (Cygnus buccinator) as seen from the observation tower at Shearness Pool. Unlike gregarious Tundra and Mute Swans, pairs of Trumpeter Swans prefer to nest alone, one pair to a pond, lake, or sluggish stretch of river. The range of these enormous birds was restricted to western North America and their numbers were believed to be as low as 70 birds during the early twentieth century. An isolated population consisting of several thousand birds was discovered in a remote area of Alaska during the 1930s allowing conservation practices to protect and restore their numbers. Trumpeter Swans are slowly repopulating scattered east coast locations following recent re-introduction into suitable habitats in the Great Lakes region.

A hen Wood Duck (second from right) escorts her young. — Wood Ducks in Bear Swamp Pool.

Black-necked Stilt and young. — A Bombay Hook N.W.R. specialty, a Black-necked Stilt and young at Bear Swamp Pool.

As the tide recedes, shorebirds leave the freshwater pools to begin feeding on the vast mudflats exposed within the saltwater marshes. Most birds are far from view, but that won’t stop a dedicated observer from finding other spectacular creatures on the bay side of the tour route road.

Tidal Marshes — Bombay Hook National Wildlife Refuge protects a vast parcel of tidal salt marsh and an extensive network of tidal creeks. These areas are not only essential wildlife habitat, but are critical components for maintaining water quality in Delaware Bay and the Atlantic.

The shells of expired Atlantic Horseshoe Crabs were formerly widespread and common among the naturally occurring flotsam along the high tide line on Delaware Bay. We found just this one during our visit to Bombay Hook. Man has certainly decimated populations of this ancient crustacean during recent decades.

Boardwalk Trail — As the tide goes out, it’s a good time for a quick walk into the salt marsh on the boardwalk trail opposite Raymond Pool.

Among the Saltmarsh Cordgrass along the trail and on the banks of the tidal creek there, a visitor will find thousands and thousands of Atlantic Marsh Fiddler Crabs (Minuca pugnax).

A male Atlantic Marsh Fiddler Crab peers from its den.

A Green Heron seen just before descending into the cordgrass to find fiddler crabs for dinner.

A juvenile Clapper Rail (Rallus crepitans crepitans) emerges from the cover of the cordgrass along a tidal creek to search for a meal.

Glossy Ibis leave their high-tide hiding place in Shearness Pool to head out into the tidal marshes for the afternoon.

Great Black-backed Gulls, Herring Gulls, and possibly other species feed on the mudflats exposed by low tide. — Great Black-backed Gulls, Herring Gulls, and possibly other species feed on the mudflats exposed by low tide in the marshes opposite Shearness Pool.

Ospey — An Osprey patrols the vast tidal areas opposite Shearness Pool.

No visit to Bombay Hook is complete without at least a quick loop through the upland habitats at the far end of the tour route.

Indigo Buntings nest in areas of successional growth and yes, that is a Spotted Lanternfly on the grape vine at the far right side of the image.

Blue Grosbeaks (Passerina caerulea) are common nesting birds at Bombay Hook. This one was in shrubby growth along the dike at the north end of Shearness Pool.

Trumpet Creeper and Poison Ivy — These two native vines are widespread at Bombay Hook and are an excellent source of food for birds. The orange flowers of the Trumpet Vine are a hummingbird favorite and the Poison Ivy provides berries for numerous species of wintering birds.

Pileated Woodpecker in Sweet Gum — The Pileated Woodpecker is one of the numerous birds that supplements its diet with Poison Ivy berries. The tree this individual is visiting is an American Sweetgum (Liquidambar styraciflua), a species native to the Atlantic Coastal Plain in Delaware. The seed balls are a favorite winter food of goldfinches and siskins.

Red-bellied Slider and Painted Turtle — Finis Pool has no frontage on the tidal marsh but is still worth a visit. It lies along a spur road on the tour route and is located within a deciduous coastal plain forest. Check the waters there for basking turtles like this giant Northern Red-bellied Cooter (Pseudemys rubiventris) and much smaller Painted Turtle.

The White-tailed Deity is common along the road to Finis Pool.

Fowler's Toad — Fowler’s Toads (Anaxyrus fowleri) breed in the vernal ponds found in the vicinity of Finis Pool and elsewhere throughout the refuge.

Turk's Cap Lily — The National Wildlife Refuge System not only protects animal species, it sustains rare and unusual plants as well. This beauty is a Turk’s Cap Lily (Lilium superbum), a native wildflower of wet woods and swamps.

Just as quail led us into the refuge this morning, this Wild Turkey did us the courtesy of leading us to the way out in the afternoon.

We hope you’ve been convinced to visit Bombay Hook National Wildlife Refuge sometime soon. And we hope too that you’ll help fund additional conservation acquisitions and improvements by visiting your local post office and buying a Federal Duck Stamp.

April 15, 2023

Photo of the Day

October 10, 2021

Photo of the Day

An Osprey takes a break from its autumn migration to do a little fishing in a tributary of Swatara Creek.

September 28, 2021September 28, 2021

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.

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!

September 13, 2021September 24, 2021

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.

August 20, 2021August 22, 2021

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…

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!

October 5, 2020October 5, 2020

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.

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.

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

September 11, 2020September 11, 2020

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…

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.

September 16, 2018January 16, 2019

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.

April 3, 2018August 15, 2022

Winter Won’t Let Go…the Birds Don’t Care

It seems as though the birds have grown impatient for typical spring weather to arrive. The increase in hours of daylight has signaled them that breeding time is here. No further delays can be entertained. They’ve got a schedule to keep.

Thursday, March 29: Winds began blowing from the southwest, breaking a cold spell which had persisted since last week’s snowfall. Birds were on the move ahead of an approaching rainy cold front.

Friday, March 30: Temperatures reached 60 degrees at last. Birds were again moving north through the day, despite rain showers and a change in wind direction—from the northwest and cooler following the passage of the front in the late morning.

Flocks of Double-crested Cormorants followed the Susquehanna River north in numerous V-shaped flocks during the recent several days.

There were Turkey Vultures by the hundreds on the way north.

Saturday, March 31: It was cooler, but birds were still on the wing headed north.

At sunrise, a migrating Northern Flicker stopped by at a suet feeder to refuel.

Osprey pairs have arrived at nest sites on the lower Susquehanna.

Sunday, April 1: The morning was pleasant, but conditions became cooler and breezy in the afternoon. Migratory and resident birds began feeding ahead of another storm.

A distant flock of fast-flying Bonaparte’s Gulls *(Chroicocephalus philadelphia)* moves expeditiously up the Susquehanna at Conewago Falls as winds begin to pick up during the late morning. Are they hurrying to get north of the path of the forthcoming weather system?

A Mourning Dove *(Zenaida macroura)* feeds in anticipation of a snowy night ahead.

A male Downy Woodpecker devours a late-afternoon meal.

This Tufted Titmouse *(Baeolophus bicolor)*, a cavity-nesting species, is distracted by a potential new home.

Dark-eyed Juncos winter in the lower Susquehanna valley. During the month of April, they will begin departing for their breeding grounds, some nesting in the mountains just to our north.

A male American Goldfinch is progressing through molt into a showy breeding (alternate) plumage.

A male House Finch takes a break from its melodious song to feed before the arrival of our next spring snow. His mate is already incubating eggs in a nest not far away.

Northern Cardinals *(Cardinalis cardinalis)* feed through the late afternoon, often as the last birds out-and-about before darkness. This male remains close to his mate as she forages beneath nearby shrubs.

Monday, April 2: Snow fell again, overnight and through the morning—a couple of inches. Most of the snow had melted away by late afternoon.

Horned Larks are plentiful in large open bare-soil (tilled) farmlands in winter, particularly near fresh manure. Their sandy-tan coloration hides them well, and they are seldom noticed unless spotted at roadside following snow storms. Horned Larks are migratory ground-nesting birds found in many sparsely vegetated habitats including tundra, parched fields and prairies, beaches, and even airports. There is a breeding population in the lower Susquehanna valley which may be increasingly attracted to favorable nesting habitat created in some no-till fields, possibly using a window of opportunity between the demise of cold-season cover crops and the ascendency of the warm-season crops to complete a brood cycle. Comparing the site selection and success rates of nesting Horned Larks under various crop management methods, including reactions to herbicide use, could be an enlightening study project for inquisitive minds. (Hint-Hint)

The dainty Chipping Sparrow has arrived. This species commonly nests in small trees, often in suburban gardens.

October 28, 2017October 31, 2017

A Quick Getaway

It was a placid morning on Conewago Falls with blue skies dotted every now and then by a small flock of migrating robins or blackbirds. The jumbled notes of a singing Winter Wren (Troglodytes hiemalis) in the Riparian Woodland softly mixed with the sounds of water spilling over the dam. The season’s first Wood Ducks (Aix sponsa), Blue-winged Teal (Spatula discors), Herring Gull (Larus argentatus), Horned Larks (Eremophila alpestris), and White-throated Sparrows (Zonotrichia albicollis) were seen.

There was a small ruckus when one of the adult Bald Eagles from a local pair spotted an Osprey passing through carrying a fish. This eagle’s effort to steal the Osprey’s catch was soon interrupted when an adult eagle from a second pair that has been lingering in the area joined the pursuit. Two eagles are certainly better than one when it’s time to hustle a skinny little Osprey, don’t you think?

But you see, this just won’t do. It’s a breach of eagle etiquette, don’t you know? Soon both pairs of adult eagles were engaged in a noisy dogfight. It was fussing and cackling and the four eagles going in every direction overhead. Things calmed down after about five minutes, then a staring match commenced on the crest of the dam with the two pairs of eagles, the “home team” and the “visiting team”, perched about 100 feet from each other. Soon the pair which seems to be visiting gave up and moved out of the falls for the remainder of the day. The Osprey, in the meantime, was able to slip away.

In recent weeks, the “home team” pair of Bald Eagles, seen regularly defending territory at Conewago Falls, has been hanging sticks and branched tree limbs on the cross members of the power line tower where they often perch. They seem only to collect and display these would-be nest materials when the “visiting team” pair is perched in the nearby tower just several hundred yards away…an attempt to intimidate by homesteading. It appears that with winter and breeding time approaching, territorial behavior is on the increase.

The second migrating Osprey of the day ran the gauntlet of marauding eagles without incident.

In the afternoon, a fresh breeze from the south sent ripples across the waters among the Pothole Rocks. The updraft on the south face of the diabase ridge on the east shore was like a highway for some migrating hawks, falcons, and vultures. Black Vultures (Coragyps atratus) and Turkey Vultures streamed off to the south headlong into the wind after leaving the ridge and crossing the river. A male and female Northern Harrier (Circus hudsonius), ten Red-tailed Hawks, two Red-shouldered Hawks (Buteo lineatus), six Sharp-shinned Hawks, and two Merlins crossed the river and continued along the diabase ridge on the west shore, accessing a strong updraft along its slope to propel their journey further to the southwest. Four high-flying Bald Eagles migrated through, each following the east river shore downstream and making little use of the ridge except to gain a little altitude while passing by.

(Top and Middle) Turkey Vultures riding the fresh breeze and teetering to-and-fro on up-tilted wings. This wing posture is known as a dihedral. (Bottom) More than 100 migrating Black Vultures climbed high on the afternoon breeze to make an oblique crossing of the river and maintain a southbound course.

Late in the afternoon, the local Bald Eagles were again airborne and cackling up a storm. This time they intercepted an eagle coming down the ridge toward the river and immediately forced the bird to climb if it intended to pass. It turned out to be the best sighting of the day, and these “home team” eagles found it first. It was a Golden Eagle (Aquila chrysaetos) in crisp juvenile plumage. On its first southward voyage, it seemed to linger after climbing high enough for the Bald Eagles to loose concern, then finally selected the ridge route and crossed the river to head off to the southwest.

Ring-billed Gulls began feeding during the afternoon as clouds preceding stormy weather approached.

CLICK ON THE LOGO FOR TODAY’S MIGRATION COUNT TOTALS

September 30, 2017September 4, 2018

Swallows by the Thousands

A fresh breeze from the north brought cooler air and a reminder that summer is gone and autumn has arrived.

Fast-moving dark clouds provided a perfect backdrop for viewing passing diurnal migrants. Bald Eagles utilized the tail wind to cruise down the Susquehanna toward Chesapeake Bay and points further south. A migrating Merlin began a chase from which a Northern Flicker narrowly escaped by finding shelter among Pothole Rocks and a few small trees. The season’s first American Black Duck (Anas rubripes), Common Loon (Gavia immer), Yellow-bellied Sapsucker (Sphyrapicus varia), and American Pipits (Anthus rubescens) moved through.

Blue Jays continued their hesitant crossings of the river at Conewago Falls. The majority completed the journey by forming groups of a dozen or more birds and following the lead of a lone American Robin, a Northern Flicker, or, odd as it appeared, a small warbler.

By far the most numerous migrants today were swallows. Thousands of Northern Rough-winged Swallows and hundreds of Tree Swallows were on the wing in search of what was suddenly a sparse flying insect supply. To get out of the brisk wind, some of the more resourceful birds landed on the warm rocks. To satisfy their appetite, many were able to pick crawling arthropods from the surface of the boulders. They swallow them whole.

A few of the thousands of swallows seen at Conewago Falls today.

September 23, 2017September 27, 2017

Blue Jay Way

The Neotropical birds that raised their young in Canada and in the northern United States have now logged many miles on their journey to warmer climates for the coming winter. As their density decreases among the masses of migrating birds, a shift to species with a tolerance for the cooler winter weather of the temperate regions will be evident.

Though it is unusually warm for this late in September, the movement of diurnal migrants continues. This morning at Conewago Falls, five Broad-winged Hawks (Buteo platypterus) lifted from the forested hills to the east, then crossed the river to continue a excursion to the southwest which will eventually lead them and thousands of others that passed through Pennsylvania this week to wintering habitat in South America. Broad-winged Hawks often gather in large migrating groups which swarm in the rising air of thermal updrafts, then, after gaining substantial altitude, glide away to continue their trip. These ever-growing assemblages from all over eastern North America funnel into coastal Texas where they make a turn to south around the Gulf of Mexico, then continue on toward the tropics. In the coming weeks, a migration count at Corpus Christi in Texas could tally 100,000 or more Broad-winged Hawks in a single day as a large portion of the continental population passes by. You can track their movement and that of other diurnal raptors as recorded at sites located all over North America by visiting hawkcount.org on the internet. Check it out. You’ll be glad you did.

Nearly all of the other migrants seen today have a much shorter flight ahead of them. Red-bellied Woodpeckers (Melanerpes carolinus), Red-headed Woodpeckers (Melanerpes erythrocephalus), and Northern Flickers (Colaptes auratus) were on the move. Migrating American Robins (Turdus migratorius) crossed the river early in the day, possibly leftovers from an overnight flight of this primarily nocturnal migrant. The season’s first Great Black-backed Gulls (Larus marinus) arrived. American Goldfinches are easily detected by their calls as they pass overhead. Look carefully at the goldfinches visiting your feeder, the birds of summer are probably gone and are being replaced by migrants currently passing through.

By far, the most conspicuous migrant today was the Blue Jay. Hundreds were seen as they filtered out of the hardwood forests of the diabase ridge to cautiously cross the river and continue to the southwest. Groups of five to fifty birds would noisily congregate in trees along the river’s edge, then begin flying across the falls. Many wary jays abandoned their small crossing parties and turned back. Soon, they would try the trip again in a larger flock.

Sensing that they are being watched, Blue Jays are hesitant to fly across the narrow Susquehanna at Conewago Falls without first assembling into a flock. The local constabulary often penalizes those who freelance and do not move in orderly groups.

A look at this morning’s count reveals few Neotropical migrants. With the exception of the Broad-winged Hawks and warblers, the migratory species seen today will winter in a sub-tropical temperate climate, primarily in the southern United States, but often as far north as the lower Susquehanna River valley. The individual birds observed today will mostly continue to a winter home a bit further south. Those that will winter in the area of Conewago Falls will arrive in October and later.

The Great Blue Heron (Ardea herodius) can be found year-round at Conewago Falls, provided there is open water and adequate food. Migrants from breeding colonies to the north will soon supplement the local population.

The Double-crested Cormorant *(Phalacrocorax auritus)* is a summer resident at Conewago Falls. Migration of the local population and of those from further north will soon begin. All will be gone by the time ice forms on the river. Cormorants are often seen drying their feathers in sunlight following a series of feeding dives.

The long-distance migrating insect so beloved among butterfly enthusiasts shows signs of improving numbers. Today, more than two dozen Monarchs were seen crossing the falls and slowly flapping and gliding their way to Mexico.

September 10, 2017September 4, 2019

Yellowlegs for Breakfast

A few nocturnal migrants flew through the moonlit night to arrive at Conewago Falls for a sunrise showing this morning. A dozen warblers were in the treetops and a Wood Thrush (Hylocichla mustelina) chattered away in the understory of the Riparian Woodlands. Three species of shorebirds were in the falls and on the Pothole Rocks: Least Sandpiper (Calidris minutilla), Lesser Yellowlegs (Tringa flavipes), and Greater Yellowlegs (Tringa melanoleuca).

A Greater Yellowlegs (right) and two Lesser Yellowlegs sandpipers dropped by for breakfast.

The diurnal migration was highlighted by a Merlin (Falco columbarius), an Osprey, and a Bald Eagle, each flying down the river. Most of the other birds in the falls seemed content to linger and feed. There’s no need to hurry folks, only trouble lurks down there in paradise at the moment.

A light to moderate flight of nocturnal migrants in the eastern United States is displayed on NOAA National Weather Service NEXRAD radar at 4:58 AM EDT. The eye of Hurricane Irma can be seen approaching the Florida Keys. (NOAA/National Weather Service image)

August 14, 2017September 4, 2019

Summer Grasses

It has not been a good summer if you happen to be a submerged plant species in the lower Susquehanna River. Regularly occurring showers and thunderstorms have produced torrents of rain and higher than usual river stages. The high water alone wouldn’t prevent you from growing, colonizing a wider area, and floating several small flowers on the surface, however, the turbidity, the suspended sediment, would. The muddy current casts a dirty shadow on the benthic zone preventing bottom-rooted plants from getting much headway. There will be smaller floating mats of the uppermost leaves of these species. Fish and invertebrates which rely upon this habitat for food and shelter will find sparse accommodation…better luck next year.

Due to the dirty water, fish-eating birds are having a challenging season as they try to catch sufficient quantities of prey to feed themselves and their offspring. A family of Ospreys (Pandion haliaetus) at Conewago Falls, including recently fledged young, were observed throughout this morning and had no successful catches. Of the hundred or more individual piscivores of various species present, none were seen retrieving fish from the river. The visibility in the water column needs to improve before fishing is a viable enterprise again.

Ospreys competing for a suitable fishing perch. Improving water conditions in the coming week should increase their success as predators.

Versatile at finding food, adult Bald Eagles are experienced and know to be on the lookout for Ospreys with fish, a meal they can steal through intimidation.

While the submerged plant communities may be stunted by 2017’s extraordinary water levels, there is a very unique habitat in Conewago Falls which endures summer flooding and, in addition, requires the scouring effects of river ice to maintain its mosaic of unique plants. It is known as a Riverine Grassland or scour grassland.

The predominant plants of the Riverine Grasslands are perennial warm-season grasses. The deep root systems of these hardy species have evolved to survive events which prevent the grassland from reverting to woodland through succession. Fire, intense grazing by wild herd animals, poor soils, drought, and other hardships, including flooding and ice scour, will eliminate intolerant plant species and prevent an area from reforesting. In winter and early spring, scraping and grinding by flood-driven chunk ice mechanically removes large woody and poorly rooted herbaceous growth from susceptible portions of the falls. These adverse conditions clear the way for populations of species more often associated with North America’s tall grass prairies to take root. Let’s have a look at some of the common species found in the “Conewago Falls Pothole Rocks Prairie”.

Big Bluestem *(Andropogon* gerardi), seen here growing in the cracks of a pothole rock. High water nourishes the plant by filling the crevices with nutrient-loaded sediment. This species evolved with roots over three feet deep to survive fires, trampling by bison, and drought.

Freshwater Cordgrass *(Spartina pectinata)* does well with its roots in water. It creates exceptional bird habitat and grows in the falls and on ice-scoured small islands in free-flowing segments of the Susquehanna River downstream.

Switchgrass *(Panicum virgatum)*, like Big Bluestem, is one of the tall grass prairie species and, like Freshwater Cordgrass, grows in near pure stands on ice-scoured islands. It takes flooding well and its extensive root system prevents erosion.

Though not a grass, Water Willow *(Justicia americana)* is familiar as a flood-enduring emergent plant of river islands, gravel bars, and shorelines where its creeping rhizome root system spreads the plant into large masses. These stands are often known locally as “grass beds”. This member of the acanthus family provides habitat for fish and invertebrates among its flooded leaves and stems. Its presence is critical to aquatic life in a year such as this.

The Conewago Falls Riverine Grassland is home to numerous other very interesting plants. We’ll look at more of them next time.

SOURCES

Brown, Lauren. 1979. Grasses, An Identification Guide. Houghton Mifflin Company. New York, NY.