With the arrival of September, many bird species start their migration to wintering grounds. Some waterfowl, such as Canada geese, are very noticeable—they fly in large flocks and their honking draws attention even when they fly at higher altitudes.

Other birds, such as the wood thrush, disappear during early fall; the only thing that is noticed is their absence.

Some hawks, falcons and other raptors migrate south as well. Many wintering bald eagles from Canada can be seen in our region during the winter months.

Our region’s breeding eagles also winter here, as there is enough open water available for them to forage for fish.

One species of raptor we don’t see after September is the broad-winged hawk. They are one of the first raptor species to migrate, and they do it in a spectacular fashion.

Whereas most raptors migrate as individuals, broad-winged hawks migrate en masse. The bulk of the migrating broad-wings come past our region just past mid-September, anywhere from the 17th to the 23rd. They take advantage of northwest winds that usually appear after a cold front passage. The wind both gives them a tailwind and provides lift along mountain ridges (orographic lift).

Frequently, the hawks find an updraft, and great numbers of broad-winged hawks use it—they can number into the hundreds and resemble a great cyclone of birds.

Broad-winged hawks are fast movers. They pass this region just past the middle of September, and by October 1, most of them have reached Mexico. Most of these hawks will winter in the northern half of the South American continent.

The nearest ridge where you might see a lot of broad-winged hawks (and other raptors) is Sunrise Mountain in Stokes State Forest in Sussex County, NJ. Other sites are further away.

Some, such as Hawk Mountain near Reading, PA, have favorable aligned ridges. They have large counts of many species of raptors. Check Hawkcount.org for sites near the region and beyond.

Hawk Mountain Sanctuary staff have collected some interesting telemetry data on several broad-winged hawks. You can explore the page at www.hawkmountain.org/conservation-science/active-research/raptor-conservation-studies/broadwing-movements.