Broad-winged hawks are on the move.  By the middle of this month their numbers will peak at Pennsylvania hawk watches.

In summer broad-winged hawks are secretive but by late August the birds have finished breeding and are ready to start their journeys to Central and South America.

Unlike most raptors, broad-wings travel in flocks, rising together in thermal updrafts, gliding out toward their destination.  At the bottom of the glide they find another thermal and rise again.  From a distance they look like rising bubbles so the flock is called a “kettle.”   The video above shows them gliding. Click here to read more about kettles.

Thermal updrafts are best over sun-heated land so the hawks avoid flying over lakes and oceans.  As they move south, the flocks grow in size and become concentrated at the northern edges of the Great Lakes and the Gulf of Mexico.  By the time they reach South Texas there are hundreds of birds per kettle and half a million broad-wing hawks per day.

To really see the sky filled with birds, visit the hawk watches at Corpus Christi, Texas or Veracruz, Mexico’s River of Raptors in the last week of September and the first week of October.

The video below shows broad-wings over Corpus Christi.  One kettle contains well over 1,000 birds!

(videos from YouTube. Click on the YouTube logo to see more information about the video)