Photo of the Day

Gray Catbird and Black Chokeberry
The fruits of a Black Chokeberry (Aronia melanocarpa) prove irresistible to this Gray Catbird.  Chokeberry is a native clump-forming shrub that reaches a height of less than ten feet.  It is tolerant of wet soils and makes a good choice for inclusion in plantings alongside streams and ponds, as well as in rain gardens.  Springtime clusters of white flowers yield berries by this time each summer.  By turning red as the fruits ripen, the foliage helps attract not only catbirds, but robins, waxwings, and other species that, in exchange for a meal, will assure dispersal of the plant’s seeds in their droppings.  With considerable sweetening, tart chokeberries can be used for juicing and the creation of jams, jellies, and preserves.

Early May Migration

National Weather Service radar showed a sizeable nocturnal flight of migrating birds early this morning.  Let’s go for a short stroll and see what’s around.

Radar returns from State College, Pennsylvania, display several bands of light rain and a massive flight of migrating birds.  (NOAA/National Weather Service image)
Birds of Conewago Falls in the Lower Susquehanna River Watershed: Gray Catbird
After coming in on an overnight flight, Gray Catbirds were numerous at dawn this morning.
Birds of Conewago Falls in the Lower Susquehanna River Watershed: Black-and-white Warbler
Masses of Neotropical migrants are just beginning to arrive.  This Black-and-white Warbler was found feeding on insects in a Green Ash tree that, so far, has survived Emerald Ash Borer (Agrilus planipennis) infestation.
Birds of Conewago Falls in the Lower Susquehanna River Watershed: Veery
The Veery is a Neotropical thrush that nests in understory vegetation on forested slopes in the Lower Susquehanna River Watershed.
Birds of Conewago Falls in the Lower Susquehanna River Watershed: Orchard Oriole
Orchard Orioles are here.
Birds of Conewago Falls in the Lower Susquehanna River Watershed: Baltimore Oriole
And Baltimore Orioles are here too.  Vibrant colors like these are what many observers find so wonderful about many of the Neotropical species.
Birds of Conewago Falls in the Lower Susquehanna River Watershed: Double-crested Cormorants
Not all migrants move at night.  While you’re out and about, keep an eye on the sky for diurnal fliers like these migrating Double-crested Cormorants, seen this morning a full ten miles east of the river.
Birds of Conewago Falls in the Lower Susquehanna River Watershed: Carolina Wren
While many birds are still working their way north to their breeding grounds, resident species like this Carolina Wren are already feeding young.  This one has collected a spider for its nestlings.

Maximum Variety

You’ll want to go for a walk this week.  It’s prime time to see birds in all their spring splendor.  Colorful Neotropical migrants are moving through in waves to supplement the numerous temperate species that arrived earlier this spring to begin their nesting cycle.  Here’s a sample of what you might find this week along a rail-trail, park path, or quiet country road near you—even on a rainy or breezy day.

The Black-throated Blue Warbler is one of more than two dozen species of warblers passing through the Lower Susquehanna River Watershed right now.  Look for it in the middle and bottom branches of deciduous forest growth.
The Veery and other woodland thrushes sing a melodious song.  Veerys remain through the summer to nest in damp mature deciduous forests.
The American Redstart, this one a first-spring male, is another of the variety of warblers arriving now.  Redstarts nest in deciduous forests with a dense understory.
Adaptable inquisitive Gray Catbirds are here to nest in any shrubby habitat, whether in a forest or a suburban garden.
Blue-gray Gnatcatchers (Polioptilia caerulea) arrive in April, so they’ve been here for a while.  They spend most of their time foraging in the treetops.  The gnatcatcher’s wheezy call alerts the observer to their presence.
Look way up there, it’s a pair of Blue-gray Gnatcatchers building a nest.
The Eastern Phoebe, a species of flycatcher, often arrives as early as mid-March.  This particular bird and its mate are already nesting beneath a stone bridge that passes over a woodland stream.
Orchard Orioles (Icturus spurius) are Neotropical migrants that nest locally in habitats with scattered large trees, especially in meadows and abandoned orchards.
In the lower Susquehanna region, the Baltimore Oriole is a more widespread breeding species than the Orchard Oriole.  In addition to the sites preferred  by the latter, it will nest in groves of mature trees on farms and estates, in parks, and in forest margins where the canopy is broken.
The Warbling Vireo (Vireo  gilvus) nests in big trees along streams, often sharing habitat with our two species of orioles.
Eastern Towhees arrive in numbers during April.  They nest in thickets and hedgerows, where a few stragglers can sometimes be found throughout the winter.
The Yellow-breasted Chat (Icteria virens) is a migrant from the tropics that sometimes nests locally in thorny thickets.  Its song consists of a mixed variety of loud phrases, reminding the listener of mimics like catbirds, thrashers, and mockingbirds.
Thickets with fragrant blooms of honeysuckle and olive attract migrating Ruby-throated Hummingbirds.  Look for them taking a break on a dead branch where they can have a look around and hold on tight during gusts of wind.
The Eastern Kingbird, a Neotropical flycatcher, may be found near fields and meadows with an abundance of insects.  In recent years, high-intensity farming practices have reduced the occurrence of kingbirds as a nesting species in the lower Susquehanna valley.  The loss of pasture acreage appears to have been particularly detrimental.
Savannah Sparrows (Passerculus sandwichensis) can be found in grassy fields throughout the year.  Large parcels that go uncut through at least early July offer them the opportunity to nest.
Male Bobolinks have been here for just more than a week.  Look for them in alfalfa fields and meadows.  Like Savannah Sparrows, Bobolinks nest on the ground and will lose their eggs and/or young if fields are mowed during the breeding cycle.
Cattail marshes are currently home to nesting Swamp Sparrows.  Wetlands offer an opportunity to see a variety of unique species in coming weeks.
Shorebirds like this Solitary Sandpiper will be transiting the lower Susquehanna basin through the end of May.  They stop to rest in wetlands, flooded fields, and on mudflats and alluvial islets in the region’s larger streams.  Many of these shorebirds nest in far northern Canada.  So remember, they need to rest and recharge for the long trip ahead, so try not to disturb them.

The Colorful Birds Are Here

You need to get outside and go for a walk.  You’ll be sorry if you don’t.  It’s prime time to see wildlife in all its glory.  The songs and colors of spring are upon us!

Flooding that resulted from mid-week rains is subsiding.  The muddy torrents of Conewago Falls are seen here racing by the powerhouse at the York Haven Dam.
Receding waters will soon leave the parking area at Falmouth and other access points along the river high and dry.
Migrating Yellow-rumped Warblers are currently very common in the riparian woodlands near Conewago Falls.  They and all the Neotropical warblers, thrushes, vireos, flycatchers are moving through the Susquehanna watershed right now.
A Baltimore Oriole feeds in a riverside maple tree.
Ruby-crowned Kinglets are migrating through the Susquehanna valley.  These tiny birds may be encountered among the foliage of trees and shrubs as they feed upon insects .
Gray Catbirds are arriving.  Many will stay to nest in shrubby thickets and in suburban gardens.
American Robins and other birds take advantage of rising flood waters to feed upon earthworms and other invertebrates that are forced to the soil’s surface along the inundated river shoreline.
Spotted Sandpipers are a familiar sight as they feed along water’s edge.
The Yellow Warbler (Setophaga petechia) is a Neotropical migrant that nests locally in wet shrubby thickets.  Let your streamside vegetation grow and in a few years you just might have these “wild canaries” singing their chorus of “sweet-sweet-sweet-I’m-so-sweet” on your property.

If you’re not up to a walk and you just want to go for a slow drive, why not take a trip to Middle Creek Wildlife Management Area and visit the managed grasslands on the north side of the refuge.  To those of us over fifty, it’s a reminder of how Susquehanna valley farmlands were before the advent of high-intensity agriculture.  Take a look at the birds found there right now.

Red-winged Blackbirds commonly nest in cattail marshes, but are very fond of untreated hayfields, lightly-grazed pastures, and fallow ground too.  These habitats are becoming increasingly rare in the lower Susquehanna region.  Farmers have little choice, they either engage in intensive agriculture or go broke.
Nest boxes are provided for Tree Swallows at the refuge.
Numbers of American Kestrels have tumbled with the loss of grassy agricultural habitats that provide large insects and small rodents for them to feed upon.
White-crowned Sparrows (Zonotrichia leucophrys) are a migrant and winter resident species that favors small clumps of shrubby cover in pastures and fallow land.
When was the last time you saw an Eastern Meadowlark (Sturnella magna) singing “spring-of-the-year” in a pasture near your home?
And yes, the grasslands at Middle Creek do support nesting Ring-necked Pheasants (Phasianus colcichus).  If you stop for a while and listen, you’ll hear the calls of “kowk-kuk” and a whir of wings.  Go check it out.

And remember, if you happen to own land and aren’t growing crops on it, put it to good use.  Mow less, live more.  Mow less, more lives.

No Need to Hurry

It’s that time of year when one may expect to find migratory Neotropical songbirds feeding among the foliage of trees and shrubs in the forests, woodlots, and thickets of the lower Susquehanna valley.

During a late afternoon stroll through a headwaters forest east of Conewago Falls outside Mount Gretna, I was pleased to finally come upon a noisy gathering of about two dozen birds.  It had, previous to that, been a quiet two hours of walking, only the rumble of an approaching thunderstorm punctuated the silence.  Among this little flock were some chickadees, robins, Gray Catbirds, an Eastern Towhee (Pipilo erythrophthalmus), and a Hairy Woodpecker (Dryobates villosus).  Besides the catbirds, there were two other species of Neotropical migrants; both were warblers.  No less than six Black-throated Blue Warblers (Setophaga caerulescens) were  vying for positions in the trees from which they could investigate the stranger on the footpath below.  And among the understory shrubs there were at least as many Ovenbirds (Seiurus aurocapilla) satisfying a similar curiosity.

The Black-throated Blue Warbler nests to the north of the lower Susquehanna valley, which it transits as a common spring and fall migrant.  On their wintering grounds, they have a thing for warm weather and the better part of a P.B. & J. sandwich.
Throughout the Susquehanna watershed, the Ovenbird is a common ground-nesting species in deciduous forests with moderately vegetated understories.  The birds seen today may have been a family group that has not yet begun the journey south.

When they depart the Susquehanna valley, these two warbler species will be southbound for wintering ranges that include Florida, many of the Caribbean Islands, Central America, and, for the Ovenbirds, northern South America.  Their flights occur at night.  During the breeding season and while migrating, both feed primarily on insects and other arthropods .  On the wintering grounds, they will consume some fruit.  It is during their time in the tropics that the Black-throated Blue Warbler sometimes visits feeding stations that offer grape jelly, much to the delight of bird enthusiasts.

Black-throated Blue Warblers and Ovenbirds commonly winter on the Florida peninsula and in the Bahamas.  With the major tropical cyclone Hurricane Dorian presently ripping through the region, these birds are better off taking their time getting there.  There’s no need to hurry.  The longer they and the other Neotropical migrants hang around, the more we get to enjoy them anyway.  So get out there to see them before they go—and remember to look up.

Category 4 Hurricane Dorian at 9:06 EDT on September 2, 2019.  If you’re headed that direction, there’s no need to hurry.  Note the cloud-free skies over much of the mainland.  (NOAA National Environmental Satellite, Data, and Information Service image)
A massive bird migration is indicated on Doppler radar in the clear skies over the eastern United States tonight (blue and green over most of the mainland).  In this loop of composite radar images from the southeastern states, note the relative absence of a flight over the Florida peninsula where the outer precipitation bands of Hurricane Dorian can be seen.  Note too that there appears to be a heavy concentration of birds flying in a southwest direction to cross the Gulf of Mexico, thus continuing their journey to Central or South America while avoiding the deadly hurricane and a much smaller tropical disturbance off the shores of Texas and Tamaulipas, Mexico.  (NOAA/National Weather Service image)

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.

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Piles of Green Tape

A couple of inches of rain this week caused a small increase in the flow of the river, just a burp, nothing major.  This higher water coincided with some breezy days that kicked up some chop on the open waters of the Susquehanna upstream of Conewago Falls.  Apparently it was just enough turbulence to uproot some aquatic plants and send them floating into the falls.

Piled against and upon the upstream side of many of the Pothole Rocks were thousands of two to three feet-long flat ribbon-like opaque green leaves of Tapegrass, also called Wild Celery, but better known as American Eelgrass (Vallisneria americana).  Some leaves were still attached to a short set of clustered roots.  It appears that most of the plants broke free from creeping rootstock along the edge of one of this species’ spreading masses which happened to thrive during the second half of the summer.  You’ll recall that persistent high water through much of the growing season kept aquatic plants beneath a blanket of muddy current.  The American Eelgrass colonies from which these specimens originated must have grown vigorously during the favorable conditions in the month of August.  A few plants bore the long thread-like pistillate flower stems with a fruit cluster still intact.  During the recent few weeks, there have been mats of American Eelgrass visible, the tops of their leaves floating on the shallow river surface, near the east and west shorelines of the Susquehanna where it begins its pass through the Gettysburg Basin near the Pennsylvania Turnpike bridge at Highspire.  This location is a probable source of the plants found in the falls today.

Uprooted American Eelgrass floating into the Pothole Rocks under the power of a north wind.  Note the white thread-like pistillate flower stem to the left and the small rooted specimen to the upper right.  The latter is likely a plant from the creeping rootstock on the edge of a colony.  As a native aquatic species, American Eelgrass is a critical link in the Susquehanna River and Chesapeake Bay food chain.  Its decimation by pollution during the twentieth century led to migration pattern alterations and severe population losses for the Canvasback (Aythya valisineria) duck.
American Eelgrass, a very small specimen, found growing in a low-lying Pothole Rock alongside the accumulations of freshly arriving material from upstream.  Note that the creeping rootstock has leaves growing from at least three nodes on this plant.  Eelgrass dislocations are regular occurrences which sometimes begin new colonies, like the small one seen here in this Diabase Pothole Rock Microhabitat.

The cool breeze from the north was a perfect fit for today’s migration count.  Nocturnal migrants settling down for the day in the Riparian Woodlands at sunrise included more than a dozen warblers and some Gray Catbirds (Dumetella carolinensis).  Diurnal migration was underway shortly thereafter.

A moderate flight of nocturnal migrants is indicated around NEXRAD sites in the northeastern states at 3:18 AM EDT.  The outer rain bands of Hurricane Irma can be seen approaching the Florida Keys as the storm closes in on the peninsula.  (NOAA/National Weather Service image)

Four Bald Eagles were counted as migrants this morning.  Based on plumage, two were first-year eagles (Juvenile) seen up high and flying the river downstream, one was a second-year bird (Basic I) with a jagged-looking wing molt, and a third was probably a fourth year (Basic III) eagle looking much like an adult with the exception of a black terminal band on the tail.  These birds were the only ones which could safely be differentiated from the seven or more Bald Eagles of varying ages found within the past few weeks to be lingering at Conewago Falls.  There were as many as a dozen eagles which appeared to be moving through the falls area that may have been migrating, but the four counted were the only ones readily separable from the locals.

Red-tailed Hawks (Buteo jamaicensis) were observed riding the wind to journey not on a course following the river, but flying across it and riding the updraft on the York Haven Diabase ridge from northeast to southwest.

Bank Swallows (Riparia riparia) seem to have moved on.  None were discovered among the swarms of other species today.

Ruby-throated Hummingbirds, Caspian Terns, Cedar Waxwings (Bombycilla cedrorum), and Chimney Swifts (Chaetura pelagica) were migrating today, as were Monarch butterflies.

Not migrating, but always fun to have around, all four wise guys were here today.  I’m referring to the four members of the Corvid family regularly found in the Mid-Atlantic states: Blue Jay (Cyanocitta cristata), American Crow (Corvus brachyrhynchos), Fish Crow (Corvus ossifragus), and Common Raven (Corvus corax).

It looks like a big Blue Jay, but it’s not.  This Belted Kingfisher (Megaceryle alcyon) takes a break after flying around the falls trying to shake a marauding Ruby-throated Hummingbird off its tail.
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SOURCES

Klots, Elsie B.  1966.  The New Field Book of Freshwater Life.  G. P. Putnam’s Sons.  New York, NY.

Suggestive Selling

A Baltimore Oriole (Icterus galbula) glowed in the first sunlight of the day as it began illuminating the treetops.  I’m not certain of the cause, but I often have the urge to dig into a bowl of orange sherbet after seeing one these magnificent blackbirds.  That’s right, in the Americas, orioles and blackbirds are members of the same family, Icteridae.  Look at blackbirds more carefully, you might see the resemblance.

Sunshine at dawn and migrating warblers were again active in the foliage.  Eight species were identified today.  Off to the tropics they go.  To the land of palm and citrus, yes citrus…limes, lemons, grapefruits, and oranges.

The Ruby-throated Hummingbirds (Archilochus colubris) are on the way toward the gulf states, then on to Central and South America.  Five dashed by the rocky lookout in the falls this morning.  Remember, keep your feeders clean, wash and rinse all the parts, and refill them with a fresh batch of “nectar”, four or five parts water to one part sugar.  Repeating this process daily during hot weather should keep contamination from overtaking your feeder.  It’s not a bad idea to rotate two feeders.  Have one cleaned, rinsed, and air drying while the second is filled and in use at your feeding station, then just swap them around.  Your equipment will be just as clean as it is at the sanitary dairy…you know, where they make sherbet.

The first of the season Caspian Terns (Hydroprogne caspia), giant freshwater versions of the terns you see at the seashore, passed through the falls late this morning.  Their bills are blood-red, not orange like the more familiar terns on the coast.  They’re stunning.

Ring-billed Gulls (Larus delawarensis) have been at the falls for several weeks.  Total numbers and the composition of the age groups in the flock change over the days, so birds appear to be trickling through and are then replaced by others coming south.  The big push of southbound migrants for this and many other species that winter locally in the Mid-Atlantic region and in the southern United States is still more than a month away.  There are still plenty more birds to come after the hours of daylight are reduced and the temperatures take a dip.

A Ring-billed Gull on the lookout for a morning snack.  They’ll eat almost anything and do a good job of keeping the river picked clean of the remains of animals that have met misfortune.  They’ll linger around landfills, hydroelectric dams, and fast-food restaurant parking lots through the winter.
Turkey Vultures (Cathartes aura) are common around the falls due to the abundance of carrion in the vicinity and because of the strong thermal updrafts of air over the sun-heated Pothole Rocks.  These rising currents provide lift for circling vultures.  We would expect migrating birds of a number of species will also take advantage of these thermals to gain altitude and extend the distance of their glides.

Some migrating butterflies were counted today.  Cloudless Sulphurs, more of a vagrant than a migrant, and, of course, Monarchs.  I’ll bet you know the Monarch, it’s black and orange.  How can you miss them, colored orange.

That’s it, that’s all for now, I bid you adieu…I’m going to have a dip of orange sherbet, or two.

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Harvey Passes By

Rain from the remnants of Hurricane/Tropical Storm Harvey ended just after daybreak this morning.  Locally, the precipitation was mostly absorbed into the soil.   There was little runoff and no flooding.  The river level at Conewago Falls is presently as low as it has been all summer.  Among the pools and rapids of the Pothole Rocks, numbers of migrating birds are building.

Mist and a low cloud ceiling created poor visibility while trying to see early morning birds, but they’re here.  The warblers are moving south and a small wave of them was filtering through the foliage on the edge of the Riparian Woodlands.  One must bend backwards to have a look, and most could not be identified due to the poor lighting in the crowns of the trees where they were zipping about.  Five species of warblers and two species of vireos were discerned.

There are increasing concentrations of swallows feeding on insects over the falls.  Hundreds were here today, mostly Tree Swallows (Tachycineta bicolor).  Bank Swallows (Stelgidopteryx riparia) numbered in the hundreds, far below the thousands, often 10,000, which staged here for migration and peaked during the first week of September annually during the 1980s and 1990s.  Their numbers have been falling steadily.  Loss of nesting locations in embankments near water may be impacting the entire population.  A reduction in the abundance of late-summer flying insects here on the lower Susquehanna River may be cause for them to abandon this area as a migration staging point.

Bank and Tree Swallows by the hundreds were feeding upon flying insects above the waters of Conewago Falls today.  Lesser numbers of Northern Rough-winged Swallows (Stelgidopteryx serripennis) and Barn Swallows (Hirundo rustica) joined the swarm.

Clear weather in the coming nights and days may get the migrants up and flying in large numbers.  For those species headed to the tropics for winter, the time to get moving has arrived.

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