Mark your calendar for the next two weeks, because one of the single greatest spectacles in North American birding is about to peak — and unlike a lot of migration events, this one doesn't require binoculars or a trained ear to appreciate. You just have to look up.
Meet the Broad-winged Hawk
The Broad-winged Hawk is a small, compact buteo — the kind of bird that's genuinely hard to find during nesting season, since it spends the summer tucked into forest habitat, rarely drawing attention to itself. But every September, that changes completely. Broad-wings become, by a wide margin, the most numerous and most spectacular raptor migrants on the continent.
Look for a stocky hawk with a banded black-and-white tail and a pale, mottled underside. But honestly, you're far more likely to notice one by the sheer number of birds around it than by field marks alone.
What Exactly Is a "Kettle"?
When Broad-winged Hawks migrate, they don't go it alone. They gather into swirling, circling flocks called kettles — named for their resemblance to steam rising and swirling out of a boiling pot. A small kettle might hold 50 to 300 birds. A large one can number in the thousands, sometimes even tens of thousands, all rising together on a single column of warm air.
Here's the mechanism: thermals are rising columns of warm air created as the sun heats the ground. Broad-wings ride these thermals upward in a slow spiral, gaining altitude while barely flapping a wing, then peel off at the top and glide toward the next thermal down the line. It's an extraordinarily efficient way to travel — hawks in a kettle expend far less energy than a bird flying solo, which matters enormously on a trip that can stretch over 4,000 miles to wintering grounds in Central and South America.
Why Right Now Is the Moment
Broad-winged Hawk migration is famous among birders for being both massive and remarkably compressed. At Hawk Mountain Sanctuary in Pennsylvania, roughly 95% of the season's entire migrating population passes through during a single two-week window in mid-September. Miss that window, and you're waiting until next year.
The numbers involved are hard to overstate. Well-known hawk watch sites in New England can see up to 10,000 Broad-wings pass over in a single day at the height of the season. Sites near the Great Lakes have recorded 50,000 in a day. Farther south, in Texas — where migration routes from across the continent funnel together — single-day counts have reached into the hundreds of thousands.
How to Watch
You don't need to be a raptor expert to enjoy this one — just the right timing, location, and a little patience:
- Go midday, not dawn. Broad-wings need thermals to form before they'll fly, so they typically don't get moving until mid-morning and stop again once thermals die down in late afternoon.
- Pick a clear, breezy day, ideally with winds out of the north or northwest — these conditions tend to produce the biggest flights.
- Find elevation if you can. Ridgelines, mountain overlooks, and established hawk watch sites exist specifically because they concentrate migrating raptors along predictable lines. Many regions have a dedicated hawk watch platform with counters on-site during peak season.
- Scan high, then wait. Kettles often start small and low, then grow as more birds join the same thermal, spiraling higher until they peel off south in a long, strung-out line.
- Don't skip your own neighborhood. While official hawk watch sites offer the best odds, Broad-wings pass over ordinary towns and cities too — a clear day this week is worth a few extra glances skyward, wherever you are.
The Greatest Show Above Earth
Birders sometimes call this "the greatest show above earth," and it's hard to argue once you've actually seen a big kettle build. Hundreds of hawks rising together in a slow, silent spiral, then breaking off one by one to glide south — it's one of the rare birding spectacles that doesn't require expertise to be genuinely awestruck by it.
You've got roughly the next two weeks. Clear your schedule for the next sunny, breezy afternoon, find some open sky, and look up.
Caught a big kettle already this season? Tell us how many you counted — we'd love to hear it.
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