Twelve-spotted Skimmer – LIFE IN THE LOWER SUSQUEHANNA RIVER WATERSHED

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 13, 2020

Look What the Wind Blew In

It’s been more than a week since Tropical Storm Isaias moved swiftly up the Atlantic seaboard leaving wind and flood damage in its wake. Here in the Lower Susquehanna River Watershed, the brevity of its presence minimized the effects.

Tropical Storm Isaias moves north-northeast across the Delmarva Peninsula.

You may have noticed some summertime visitors flying about during these hot humid days that followed Isaias’ passing. They’re the dragonflies.

Our familiar friend the Wandering Glider is widespread throughout the valley right now—dropping eggs on shiny automobile hoods that look to them like a nice quiet puddle of water.

The Wandering Glider is a global traveler. Here in the lower Susquehanna valley, it is currently abundant around still water and in large parking lots.

Each of the other common migratory species is here too. Look for them patrolling the skies over large bodies of water and over adjacent fallow land and meadows where tiny flying insects abound. Did these dragonflies arrive on the winds associated with the tropical storm, or did they move in with the waves of warm air that followed it? Probably a little of both.

The Common Green Darner, a large dragonfly, can be the most abundant of the migratory species. Watch for high-flying swarms in the coming weeks.

The Black Saddlebags is recognized in flight by the black base of each hindwing. These patches give the appearance of a pair of saddlebags draped across the dragonfly’s thorax.

The Twelve-spotted Skimmer(Libellula pulchella) is a regular migrant.

The Prince Baskettail (Epitheca princeps) can occur among mixed groups of dragonflies. Despite it rarely being mentioned as a migrant, its proclivity for non-stop day-long flight makes it a likely sighting among sizeable swarms.

Big swarms of dragonflies don’t go unnoticed by predators—particularly birds. The southbound migration of kites, Broad-winged Hawks, American Kestrels, and Merlins often coincides with the swarming of migratory dragonflies in late summer. Each of these raptors will grab and feed upon these insects while on the wing—so keep an eye on the sky.