For the Birds Radio Program: Broad-winged Hawk
Tens of thousands of Broad-winged Hawks fly over Duluth every September.
Transcript
![Broad-winged Hawk] (http://farm5.staticflickr.com/4090/4987157387_8fdf0fb636.jpg “Broad-winged Hawk”)
(Recording of a Broad-winged Hawk)
No, that wasn’t a songbird–that was the call of the Broad-winged Hawk.
(Recording of a Broad-winged Hawk)
The broad-wing is a gentle, tame hawk–common in the northwoods all summer. If you’ve ever seen a chunky crow-sized hawk sitting on a telephone wire as you drove past, it was probably a broad-wing– especially if it let you walk right up to it for a closer look.
Broad-wings belong to a group of hawks called buteos–in Britain they’re called buzzards. The hawks in this group have long, wide wings and short, wide tails–ideal for floating on updrafts and thermal air currents without flapping. Most buteos, like our Red-tailed Hawk, hunt on the wing in this way. The Broad-wing is unusual in that it doesn’t hunt from the air. But it does show its buteo inheritance in its migratory behavior. Migrating Broad-wings collect in huge flocks, called kettles. Hundreds of them swirl about on vertical thermals before streaming out on an air current which carries them to the next thermal. This method probably helps them to conserve energy on their long migration flight to Central and South America. Broad-wings are truly fair-weather friends–by the time the snow flies, they’re usually long gone, and don’t return to Minnesota until late March or April.
Like many species of hawks, Broad-wings are devoted mates and parents, belying their macho image. It takes a pair of Broad-wings almost three weeks to build the nest each spring, and they are very fussy about its appearance—they usually brighten the nest with sprigs of fresh green leaves which they keep fresh throughout the nesting period. This was perhaps the evolutionary origin of florists and interior decorators. Both parents incubate the eggs, although only the female develops a brood patch—an area of her belly where the feathers drop out and the skin becomes engorged with blood vessels to better warm the eggs.
Broad-winged Hawks eat mainly insects–like June bugs, dragonflies, and grasshoppers–and snakes, frogs, toads, and small woodland mammals. When young songbirds are just learning to fly, they are sometimes taken, although the Broad-wing, like other buteos, is too big and clumsy to be good at catching birds as a rule.
Broad-winged Hawks migrate through Duluth in huge numbers. This year, on September 13, 16,000 of them were counted passing over Hawk Ridge. Although this was a good day, it was far from the best single day on the ridge. On September 15, 1978, almost 32,000 Broad-wings were carefully counted. The swarming kettles of birds are impossible to even estimate—experienced hawk counters wait until a kettle starts to stream out before counting the birds passing along in a more manageable line.
Although the large numbers of Broad-wings that gather here make it seem as if this species were invulnerable, it isn’t. On their South American wintering grounds, they are shot at and exposed to DDT. The consistent counting of this bird at places like Hawk Ridge helps to monitor the species, to insure that if the numbers do drop dangerously, people will notice in time to save this noble bird of prey.
(Recording of a Broad-winged Hawk)
This is Laura Erickson, and this program has been “For the Birds.”