According to migration statistics from Hawkcount.org, the bulk of broad-winged hawk migration passed through Pennsylvania in mid-September with one last pulse last Tuesday.

Most of them followed Kittatinny Ridge, the easternmost spine of the Appalachian Mountains where Hawk Mountain Sanctuary is located.  Here are the three highest broad-winged counts at Hawk Mountain this month:

• Sept 13 — 1,572
• Sept 17 — 2,813
• Sept 19 — 1,701

What’s unusual about broad-wings is that they travel in flocks (most raptors don’t) and they watch each other for flight cues.  If one hawk finds a thermal with good lift, others fly over and rise on it as well.  Soon they form a “kettle” of hawks stirring round and round in the rising air.  As each one  reaches sufficient altitude it sets its wings and glides southward to find the next thermal.

After the broad-wings leave Pennsylvania they make their way to the Texas Gulf Coast and follow the eastern edge of the Gulf of Mexico on their way to their wintering grounds in South America.  By the time they pass Veracruz, Mexico, all the broad-wings of North America are concentrated in a narrow corridor.  Their numbers at Veracruz are astonishing, as shown in their three highest counts this month and in the video above.

• Sept 23 — 136,376
• Sept 24 — 128,272
• Sept 22 —  68,724

I tried to imagine 136,000 hawks in my Pittsburgh neighborhood and my first thought was, “There isn’t enough food here for 136,000 hawks!”

Broad-winged hawks eat small mammals, reptiles, amphibians, large insects and songbirds.  Right now they’re traveling with millions of dragonflies and songbirds who are also on migration.

That’s why they migrate in September.  That’s why there’s a spectacle of broad-winged hawks.

(video from Veracruz Hawkwatch on YouTube)