The Crow Brothers: Why My Best Security System Has Feathers

There’s a particular sound that empties my barnyard in about a second and a half. It’s not the feed bucket — that fills the barnyard. It’s a hard, flat, repeated caw coming from up high and moving fast, and the instant the girls hear it, every hen in the yard is under the coop before I’ve so much as looked up from what I’m doing.

That sound is the crows. And when the crows are hollering like that, it means there’s a hawk somewhere overhead that is about to have a very bad afternoon.

Meet the brothers

There are three of them, and they run this yard like they own the deed to it. I’ve named them, because they earned it.

Bruce is the one in charge. He showed up two springs ago, took one look at my flock, and apparently filed some paperwork with himself declaring the whole operation his personal responsibility. He is enormous, he is opinionated, and he watches the sky the way a lifeguard watches a public pool full of toddlers.

Cletus is the lieutenant. Where Bruce is all authority, Cletus is all enthusiasm — the first one airborne, the loudest one hollering, occasionally the one hollering about nothing at all. Every security team has a Cletus.

Jeff is the third brother. Jeff mostly watches. I have never once seen Jeff start anything, but I have also never seen a hawk finish anything on Jeff’s watch, so I’ve decided not to ask questions about Jeff.

The three of them showed up together, they patrol together, and around here they’ve got a reputation I can neither confirm nor deny involving a certain incident at the O.K. Corral. I don’t ask. They don’t tell.

Do crows actually protect chickens? (Yes — and here’s why)

Now, I could tell you all this and you’d be within your rights to file it under “farm lady got attached to some birds.” So I went and looked it up, and it turns out the science is squarely on the crows’ side.

When crows harass a hawk or an owl, biologists call it mobbing — a group of smaller birds ganging up on a bigger predator to drive it off. The goal usually isn’t to kill the hawk. It’s to make the neighborhood so loud, so annoying, and so obviously watched that hunting there simply isn’t worth the trouble. A big part of the effect is that mobbing blows the hawk’s cover. Raptors hunt by ambush; they need surprise. A pack of crows screaming its head off strips that surprise away entirely, and a hawk that’s been spotted is a hawk that’s already lost. It is not a subtle operation, either —

a photographer in Perth once caught the whole thing mid-air: a barn owl flushed out in daylight and set upon by a mob of ravens and magpies, so thoroughly outnumbered that its only move was to leave. That’s more or less what my three sound like every time a hawk gets ambitious over my yard.

Do it often enough and researchers describe something like a “landscape of fear” — predators start avoiding the areas where they keep getting mobbed. The crows aren’t just winning one fight. They’re teaching every hawk in the county that this particular acre is more headache than it’s worth.

The part that surprised me

Here’s the bit that made me sit down on the workbench with my strawberry lemonade and actually think about it.

There’s a whole body of research on what scientists call protective nesting associations — the tidy fact that all sorts of animals deliberately set up house near a bigger, meaner, more territorial neighbor specifically to borrow their protection. A 2008 review in the ornithology journal Ibis pulled together dozens of documented cases of exactly this. Little birds nesting near aggressive raptors. Geese nesting a careful distance from falcons. In one well-studied case, red-billed choughs that nest near lesser kestrels raise more chicks than the ones that don’t, because the kestrels chase off the nest robbers and never bother the choughs themselves.

The upshot is simple: if you can’t be the toughest thing in the yard, live next to the toughest thing in the yard.

Which is, when you get right down to it, exactly what my hens are doing. They’re not paying Bruce. Bruce isn’t defending them — he’s defending his turf, and the girls just happen to live inside the fence line he’s decided is his. But the benefit lands on my flock all the same. Free aerial security, twenty-four hours a day, paid entirely in whatever the crows can pilfer from the compost pile.

They also hold a grudge

One more thing worth knowing about crows, because it explains a lot about why they’re so good at this job: they remember faces. And I don’t mean vaguely.

Researchers have shown that American crows can learn to recognize a specific individual who wronged them — and remember that individual for years. Worse (or better, depending on which side you’re on), they’ll tell the other crows. A crow that has never met you can learn from the flock that you are trouble and start scolding you on sight. They keep records. They share notes. They do not forgive.

So when Bruce fixes a hawk with that flat black stare and starts making calls, that’s not a bird reacting in the moment. That’s a bird who remembers last time.

The sisters he never had

I know, in my head, that crows don’t form attachments to chickens. The books are clear on this. The crows are defending real estate, not friends.

Nobody has explained this to Bruce.

As far as he’s concerned, those twenty-some hens scratching around under his gate post are his sisters, and anything with talons that drifts across this sky is going to answer to him for it. He’s wrong about the biology. He’s exactly right about the job. And I’ve stopped correcting him, because a farm could do a lot worse than a guardian who’s decided, against all evidence, that the flock is family.

I owed them something for all that. So I asked my friend Bonnie — the one who painted the folk-art signs for my hen house back in June — to make them a porch leaner, and that’s a story for the Crafting Blog.

The chickens still don’t thank the crows. The crows don’t seem to need it. And I appreciate the whole feathered lot of them enough to make up the difference.

— Pearl