American Kestrel Eating “Grit”
I don’t have any beautiful photos today but I do have some interesting behavior. Yesterday morning, I came across this female American Kestrel sitting in the middle of a large, isolated, gravel parking lot/camping area on Antelope Island. I thought it was an unusual resting place for a kestrel and as I approached her in my pickup I was even more intrigued when she didn’t immediately fly off, as this species typically does. She repeatedly took a couple of wingbeats and flew a few feet, but never far. She was, for some reason, reluctant to leave and at first I couldn’t figure out why. I was eventually able to work my way close enough to her to see that she was swallowing small stones from the gravel parking lot. This was a behavior that I’d never seen before in a raptor, though I’ve often seen it in other birds. As a biologist, I’m aware of the general function of the gizzard in birds – that seed eating birds swallow “grit” to act as teeth (birds have no true teeth, presumably a weight saving adaptation for flight) within the grinding gizzard so they can physically break down their hard food and prepare it for chemical digestion. And it had been my understanding that raptors don’t consume grit because they don’t eat seeds. The flesh they consume is easily digested and doesn’t need to be physically broken down first. So why is this little falcon swallowing small stones? I decided to ask Mark Runnels, an extremely knowledgeable master falconer from Oklahoma and…