A few kinds of diurnal raptors are suddenly noticed in Lancaster County, Pennsylvania more commonly in September than they were during summer. Those raptors are migrating ospreys, bald eagles, broad-winged hawks and American kestrels. But a person needs to know when and where to look for these migrants birds to be able to spot them.
These raptors are not confined to migrating in September. They started their push south for the winter in August and will continue to do so through October, though we won't see broad-wings in Lancaster County during that latter month.
Ospreys are catchers of larger fish they pick from near the surfaces of creeks, rivers and impoundments. Therefore, they are most likely seen along those bodies of water during their migrations south, though they are spotted overland as well. Here in Lancaster County we see them mostly along the Susquehanna River, the Conestoga River and most any impoundment. They are always thrilling to see.
Ospreys are big and stately. They are white below and dark on top, with white heads and a dark band through each eye. When fishing, they hover into the wind while watching the water. When a finny victim is spotted, each osprey drops feet-first into the water to snare it in its long, sharp talons. Then the osprey flies out of the water and to a rock or tree perch to eat its prey.
A few pairs of ospreys nest along the Susquehanna River here in Lancaster County. But those we see here in autumn had come from waterways and impoundments farther north and are making their way farther south to waters that won't freeze in winter.
Several pairs of bald eagles nest in Lancaster County and surrounding counties along the Susquehanna River. A few pairs also raise young at impoundments and by creeks in farmland. But many balds come through this area during late summer and fall and are mostly spotted around bigger waterways and impoundments, including in cropland, where they search for larger fish.
Mature balds are huge and dark all over with white heads and tails. Immatures are dark all over, mottled a bit with white. All ages are majestic perched or soaring on high.
Bald eagles catch live fish by swooping low to the water and plucking their victims from the surface with their powerful claws, without entering the water as ospreys do. But balds also scavenge dead fish, and any other creatures, as vultures do.
Some bald eagles winter in Lancaster County and surrounding counties where they catch live fish from ice-free waters or scavenge carcasses wherever they find them, including dead chickens and other farm animals in agricultural areas. We often see two kinds of vultures, American crows, red-tailed hawks and bald eagles scavenging dead livestock in farmland in winter.
Broad-winged hawks migrate through this area during September, with a peak of migration around September 20. They are gone from northeastern North America by the end of the month.
Broad-wings nested in forests in northeastern Pennsylvania, eastern New York State, New England and eastern Canada. And they are the only hawk species in eastern North America that migrates in flocks of score, hundreds, and even thousands at times, creating magnificent spectacles.
On a typical warm, sunny day in Lancaster County in September, I have stood south or southwest of a woodlot by 9:00 am and watched the sky over the woods for broad-wings. Sometimes I first see turkey vultures soaring up from the woods, then one or two broadies. Within minutes, several broad-winged hawks circle over the woods and neighboring fields as they search for a thermal of rising air warmed by sunlight shining on bare ground fields, blacktop roads and buildings in the area. I can see the broad-wings swirling upward in a thermal, higher and higher, until they reach the zenith. Then they peel off, one after the other, and soar swiftly to the southwest in long lines. Gravity gradually pulls them down, so they are obliged to seek another thermal, and another, all day. But those thermals carry them on long migrations to Mexico, Central America and South America with little effort. There they winter until early March when they start north again.
American kestrels rear offspring sparingly in tree cavities, barns and nest boxes erected for them or screech owls in farmland in this area. But by late August and September, I suddenly see kestrels perched on roadside wires in cropland where I had not seen them all summer. These are migrant kestrels, a small cousin to peregrine falcons, looking for mice, grasshoppers and small birds along country roads and neighboring fields. Some of those kestrels will continue going farther south for the winter, but some others will winter in local farmland, preying mostly on mice and small birds.
Look for these migrating diurnal raptors this September or succeeding ones. They are exciting and inspiring to see soaring southwest or south to escape the northern winter.
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