Black-throated Green Warbler – LIFE IN THE LOWER SUSQUEHANNA RIVER WATERSHED

September 5, 2021September 5, 2021

Warblers Passing Through the Lower Susquehanna River Valley

Neotropical birds are presently migrating south from breeding habitats in the United States and Canada to wintering grounds in Central and South America. Among them are more than two dozen species of warblers—colorful little passerines that can often be seen darting from branch to branch in the treetops as they feed on insects during stopovers in the Lower Susquehanna River Watershed.

Being nocturnal migrants, warblers are best seen first thing in the morning among sunlit foliage, often high in the forest canopy. After a night of flying, they stop to feed and rest. Warblers frequently join resident chickadees, titmice, and nuthatches to form a foraging flock that can contain dozens of songbirds. Migratory flycatchers, vireos, tanagers, and grosbeaks often accompany southbound warblers during early morning “fallouts”. Usually, the best way to find these early fall migrants is to visit a forest edge or thicket, particularly along a stream, a utility right-of-way, or on a ridge top. Then too, warblers and other Neotropical migrants are notorious for showing up in groves of mature trees in urban parks and residential neighborhoods—so look up!

A Black-and-white Warbler descends into the tangles of the forest understory to search for a morning meal of insects or creepy-crawlies.

Success! Looks like a cranefly (Tipulidae).

A Black-throated Green Warbler high in the treetops.

Warblers often travel and feed in the company of other Neotropical species like this Red-eyed Vireo.

Get out and look for those Neotropical migrants now because, like this Canada Warbler, in just a few weeks they’ll be gone.

Be sure to visit the “Birds of Conewago Falls” page by clicking the tab at the top of this page. There, you’ll find photographs of many of the lower Susquehanna valley’s bird species, including the warblers and other Neotropical migrants.

September 13, 2020October 4, 2020

A Visit to Second Mountain

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

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

A Black-and-white Warbler (Mniotilta varia) searching the trunk of a tree for insects.

A Blackburnian Warbler high in the forest canopy.

A Black-throated Green Warbler bouncing from branch to branch as it feeds.

A Chestnut-sided Warbler lurks among the foliage.

One of a hundred or more Red-eyed Vireos found swarming the treetops, and occasionally the understory, while engaging in a wild feeding frenzy.

A male American Redstart. Judging by that gray hood, it’s probably experiencing its second fall migration.

Eyes were skyward at the Second Mountain Hawk Watch lookout as Broad-winged Hawks began streaming through during the mid-morning.

During the morning flight, Broad-winged Hawks including this adult floated by the lookout riding updrafts created by the south wind striking the face of the mountain ridge.

As the overcast became more scattered and more sunlight reached the ground, Broad-winged Hawks began riding thermal currents to gain altitude before gliding off to the southwest in continuance of their long trip to the tropics. At times, birds would disappear into the base of the clouds before ending their climb and sailing away.

Broad-winged Hawks rely principally upon amphibians and large insects like this bush katydid (Scudderia species) for sustenance. With freezing temperatures just around the corner, “broad-wings” must make their way to warmer climes early or risk starvation.

A Bald Eagle always gets observers looking.

One never quite knows what one may see when having a look around.

A Cape May Warbler (Setophaga tigrina) in the lookout hemlock.

A Black Saddlebags, one of several migratory dragonflies seen today.

An Osprey glides through in the afternoon glare.

A speedy Merlin thrilled observers with a close approach.

One must remember that Fort Indiantown Gap is an active military installation, so from time to time training and drilling exercises may interrupt bird observation activities at the Second Mountain Hawk Watch.

Today, speedy A-10 Warthog attack aircraft piloted by members of the Maryland Air National Guard based at Glenn Martin Field thrilled observers on the lookout with several close passes during their training runs.

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

September 12, 2020September 14, 2020

Big Fallout

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

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

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

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

A Broad-winged Hawk lifts off from the cover of the forest where it spent the night.

The same Broad-winged Hawk (bottom) and an adult Bald Eagle gain altitude on a thermal updraft before the former glides away toward the southwest.

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)

CLICK ON THE LOGO FOR TODAY’S MIGRATION COUNT TOTALS

September 3, 2017September 3, 2017

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.