For the Birds Radio Program: Migration Report

Original Air Date: Aug. 31, 2004

Hawk migration is starting to pick up right now.

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Transcript

Hawks are on the move! Last week when I was working at my desk, the crows started making a fuss, and I looked up to see several of them chasing an immature Cooper’s Hawk into the box elder just outside my window. The hawk landed in the limb closest to the window, checking every which way to make sure the crows were gone, and suddenly its eyes met mine. I’d love to say that at that moment the earth moved, or that I had some mystical epiphany, but I simply took note of the yellow irises as he pulled his head back as if in surprise to have unexpectedly come upon a human staring at him from what had seemed like a perfectly safe retreat, and he instantly took off. I use the word “he” advisedly, because I’ve seen Cooper’s Hawks in the same tree before, and this one didn’t look quite big enough to be a female.

In all raptor species, the female is larger, and usually more aggressive, than the male. There’s no such word as “macho” in the world of hawks: the word is “macha.” And the difference is largest within the accipiters. Why the marked difference? When a pair is two different sizes, the larger can focus on larger, slower prey while the smaller can shoot for tinier, quicker animals. Why is it the female who is the larger? Hawks are fierce hunters who take advantage of just about every possibility to catch a meal. They live on the very cusp where life and death meet, and if they allow a potential meal to pass, chances are their genetic line will die out, so they are always on red alert, these lean, mean killing machines. But when a pair come close, particularly at the critical moment when the male is on the female’s back, if he forgets that she is his mate and not his lunch, their genetic line will die out, too. Since the female is the one in the vulnerable position during mating, she’s the larger—all she has to do is fix him with a long, hard stare and he will be very very careful. The size difference is naturally most dramatic in the fiercest hawk group of all, the one that feeds most heavily on birds, the accipiters.

Several times I’ve heard the crows make a fuss, and looked out to see a hawk passing over. As they do every year, the crows are adapting to the migration, and now only kick up a ruckus if the hawks come through below treetop level. They’re not paying attention to Bald Eagles circling high in the blue sky, well above hunting distance, but when I look up, if I scan the sky thoroughly, I more often than not pick out at least one raptor.

Robins are paying attention to the migration, too. Like crows, they don’t worry about eagles soaring above, but whenever an accipiter or Merlin flies over, they make a high-frequency call that is a warning to every bird that a dangerous hawk is approaching. Several other songbirds, including chickadees, have a similar high-pitched see call, and all use it as a warning about accipiters or falcons. Birds look up to see where the danger is. Either way, attention must be paid.

Throughout the coming weeks, hawk migration will intensify. Last year on September 15, over a hundred thousand hawks were counted passing over a single overlook in Duluth, though really, the entire north shore is a migration pathway. Anywhere in Duluth, one can look up during migration with a good chance of spotting a hawk or two. The first front of migration, during which there may be tens of thousands of Broad-winged Hawks in a single day, will peak in the next few weeks. Best time of day is generally from about 10 am through about 3 or 4 pm. If you can break away for lunch, head out to the Lakewalk, Brighton Beach, Enger Park, Hawk Ridge, or any other spot where you can look up to the skies and enjoy this annual spectacle. And if you’re stuck at your desk, look out the windows every now and then. Migration is like a box of chocolates—you never know what you’re going to get.