Today brings us to the end of Peregrine Week, celebrating one of evolution’s marvels. I’ve bought new binoculars just to see these birds—there are over a dozen pairs in Chicago, some right here on campus—and I’ll be watching the nests come spring. And if you’ve liked the excerpts from J. A. Baker’s The Peregrine, by all means buy the book.
Here’s a video of a peregrine repeatedly dive-bombing a flock of starlings. Notice how during the attack they stay together as a group; this is almost certainly for protection. A falcon can’t simply dive into a big flock of starlings, hoping to catch one—that would be suicide. It has to single out one bird and go for it. And that’s hard when all the birds are so thickly massed together. Note too how the birds seem to move as a unit.
The huge flocks of starlings that form in the evening, and are often seen in Britain, are called murmurations. They can number in the hundreds of thousands. The video below explains some theories about why these huge flocks form, but one of the biggest mysteries is how so many birds can move together so quickly, changing direction almost instantly. You’d think that if each bird followed its neighbor, a flock could change direction no more quickly than the sum of individual reaction times of the birds across the diameter. But it’s much quicker than that. Do the birds follow birds on the periphery of the flock rather than their neighbors? Who decides to change direction? This is an unsolved problem in animal behavior.
Below we see a huge murmuration of starlings in England, near Oxford. I’ve had the privilege of seeing this once in my life: near St. Andrews in Scotland. It’s an aurora borealis of birds!
The recovery of the peregrine falcon, once on the verge of extinction, is one of the great success stories of conservation. This video tells you a bit about it.
[The hawk] returned an hour later, and perched in an apple tree at the edge of open ploughland. I sat and watched him from thirty yards, away from all cover. After two minutes of uneasy glaring, he flew straight at me as though intending to attack. He swept up into the wind before he reached me, and hovered twenty feet over my head, looking down. I felt as a mouse must feel, crouching unconcealed in shallow grass, cringing and hoping. The hawk’s keen-bladed face seemed horribly close. The glazed inhuman eyes—so foreign and remote—swivelled like brown globes in the long sockets of the moustachial bars. The badger-colored face was vivid and sharp against the sky. I could not look away from the crushing light of those eyes, from the impaling horn of that curved bill. Many birds are snared in the tightening loop of his gaze. They turn their heads towards him as they die. He returned to the tree, unsatisfied, and I left him alone for a while.
–J. A. Baker, The Peregrine