Hawks and other birds are migrating south this month, but unlike most other birds, hawks, for the most part, don’t flap their wings while they fly. I’m Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.
When they soar through the skies, hawks take advantage of phenomenon known as a thermal – basically a warm bubble of air risisng off the ground.
“Hawks get in those bubbles and rise up on outstretched wings, much like riding an elevator or an escalator into the sky.”
Robert DeCandido is the Chief Naturalist of New York City’s Urban Park Rangers.
“Generally, we see them circling overhead, long lazy circles, and as they’re doing this going round and round, they’re gaining altitude. Once they’re at the top of that thermal, they spill out of it, and then seek out the next thermal.”
Once the hawk begins its gliding descent off of the thermal, how does it know where to find the next bubble of air?
“If you’re a hawk, and you have eyes that are that good, you may see insects rising in a certain place, or you may see leaves, or grass, or paper, even, rising up. You head in that direction.”
Although it might take a little longer to get from one place to another, riding the thermals pays off in energy savings.
“It’s a lot easier to fly in that manner, you also don’t use as much energy, which means you can spend most of your day preening or in the safety of perching in the trees, rather than doing a dangerous thing like crashing through limbs of trees and branches in search of prey. So in many ways thermals save energy, they get you to one place to another fuel-efficiently and safely.”
Thermals aren’t the only weather phenomenon that hawks take advantage of. We’ll hear more in future programs. Pulse of the Planet is presented by the American Museum of Natural History. I’m Jim Metzner.