The American Kestrel: Portland’s Smallest Falcon

There is a falcon in Portland that weighs about four ounces — roughly a deck of cards — and most people drive past several a week without registering that the small bird on the wire is a bird of prey at all.

The American kestrel. Smallest falcon on the continent, painted like nothing else here, and in more trouble than it looks. Every photograph below is the same species, all of them males, photographed here in Oregon across several seasons.

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Why the Head Moves Like That

Start with the face, because the face explains the behavior.

A kestrel’s eyes are enormous relative to its skull — proportionally far larger than yours, filling so much of the head that the two eyeballs nearly meet behind the beak. Packed in that tightly, there is essentially no room for the muscles that would swivel them. The eyes are fixed in their sockets. So to look at anything, a kestrel must move its whole head, which is why every raptor you have ever watched turns with that abrupt, mechanical snap. What reads as fierce concentration is partly just the only method available.

What those eyes buy is worth the inconvenience. You have one fovea per eye — the small pit at the back of the retina where vision is genuinely sharp, which is why you have to point your eyes at whatever you want to read. A kestrel has two foveae in each eye: one facing forward for binocular work, and a second angled roughly forty-five degrees out to the side.

So a raptor cocking its head sideways is not glancing vaguely. It is bringing its sharpest vision onto something well off to one side, at an angle where your eyesight would be a soft blur.

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The resolution is genuinely hard to credit. A kestrel can pick out an insect barely an inch long from sixty feet up — not as a suspicious speck worth investigating, but resolved well enough to decide whether it is worth the trip down.

And what he is looking at, up there, is probably the reason he is looking at all. A four-ounce falcon sitting in the open is a meal for anything larger. The exposed perch is a bargain struck fresh every day: the best possible view of dinner, in exchange for being extremely visible to whatever is hunting him.

Watch a perched one for a minute and you will see the head bobbing — small deliberate shifts, side to side, up and down. That is not nerves. Unable to swivel his eyes, he moves his whole head to change viewpoint and reads distance from how much the world slides against the background. He is triangulating.

Telling One From Everything Else

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Four marks, and the first one does most of the work.

Two black stripes on each white cheek. Every kestrel wears both — male, female, adult, juvenile. One runs below the eye, one further back. No other small raptor in Oregon has the pair.

A dark eye. Near-black, as every falcon’s is. If the eye is pale yellow, you are not looking at a falcon at all — you are looking at a young accipiter, and I speak from experience. I once published a juvenile Cooper’s hawk as a merlin, and it was the pale eye and the clean cheek that eventually gave it away. That correction is here, and this bird is the control specimen.

Rufous. Warm rusty red on the back and tail. Merlins have none of it — they are brown or slate, and our local Black Merlin is sootier still.

The tail. Which deserves its own photograph.

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Rufous, crossed near the end by one broad black band, finished with a white tip. That single bold band is the mark. A merlin’s tail is dark with several narrow pale bands instead. It is the fastest way to separate the two small falcons, and it works at distances where nothing else is readable.

There is also a piece of face-paint research worth knowing. That dark stripe under a falcon’s eye works like the black an outfielder smears on his cheekbones — absorbing light that would otherwise bounce off pale feathers into the eye. What lifts it above a plausible guess: when researchers compared peregrine falcons from populations around the world, birds living under the strongest, most consistent sunlight had the boldest, widest malar stripes. The marking tracks the glare.

He and She

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Here is something genuinely unusual. In nearly every raptor, males and females look alike and differ only in size — a female red-tailed hawk is simply a bigger red-tailed hawk. Kestrels break that rule.

Males carry blue-gray wings over a rufous back, a chest spotted with round black dots, and a tail with one wide black band. Females are rufous on wings and back, barred throughout, streaked rather than spotted down the front, with many narrow tail bands. They are one of the very few raptors anywhere you can sex from a photograph on color alone — and they keep the usual arrangement on top of it, since the female is the larger bird.

Every kestrel on this page is a male. I have yet to get a female worth showing you.

In winter they even live apart. Males tend to hold the wooded and shrubby edges; females take the wide open country. Nobody is certain whether the larger females simply push the males off the better ground or whether the two genuinely prefer different habitat, but the pattern is consistent enough that where you find one is a fair hint at which one you found.

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How They Actually Hunt

Kestrels are famous for hovering, and it is a marvelous thing to watch — the bird holds a fixed point over a field, wings beating, while its head stays so perfectly still it looks pinned in the air. On a good breeze it will hang there almost motionless, riding the wind like a kite on a string. The spread tail is the control surface, trimming continuously against every gust so the head never moves.

But hovering is the fallback. Most kestrel hunting is done sitting down — from a wire, a pole, a bare branch, watching the ground. Hovering is for country that offers nothing to perch on. Sitting is free; flying is not.

And they hunt with a sense we do not have. Kestrels see into the ultraviolet, and the urine and scent trails voles leave along their runways reflect UV light. The work that established this was done on their European cousins, and the implication is remarkable: a kestrel hovering over a meadow is not scanning hopefully for movement. It is reading a glowing map of where the rodents have been.

The old name for the bird was sparrow hawk, which is wrong twice over. It is not a hawk, and it does not mainly eat sparrows. Through the warm months a kestrel’s diet leans heavily on insects — grasshoppers, dragonflies, beetles, cicadas. Voles and mice carry it through winter; small birds are occasional. The fiercest-looking thing on the fence line spends much of the year hunting grasshoppers.

When hunting goes well they plan ahead, caching the surplus in a grass clump or a fence-post hollow and returning for it later, sometimes days later. A bird this small cannot afford many blank days in a row, so it keeps a pantry. On cold nights it does something most falcons do not, and tucks into a cavity to roost — trading the open branch for a few insulated degrees until morning.

The Earliest Nesters

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Bare branches, catkins open, no leaves — that is very early spring, and it puts this bird in the middle of the most interesting few weeks of his year. Kestrels are among the earliest raptors to nest, getting started while the trees are still bare.

The courtship is worth going out for. The male flies a climbing, diving, fluttering display over the territory, calling the whole way — a sharp rapid klee-klee-klee-klee that carries a long way over open ground. Then he hunts for two, catching prey and passing it to the female, sometimes in mid-air, for weeks before she lays a single egg. She is assessing whether he can feed a family. It is a job interview conducted entirely in voles.

That call, incidentally, is where the name comes from. Kestrel traces back through Old French to a word imitating the clattering cry. Most bird names describe a color or honor a naturalist; this one is just the noise the bird makes, written down several centuries ago.

Notice too what he is landing on: the topmost twig of a bare tree, thinner than a pencil, in wind. Kestrels take the highest available perch almost without exception — and the higher and thinner it is, the more it moves the instant they touch it. He has to arrive with almost no forward speed and then hold his balance on something still swaying. The raised wings and the fanned tail are both still working after contact.

One more tell, once you start looking: a kestrel that has just landed will pump its tail two or three times as it settles. A quick downward bob, then stillness. You will end up identifying birds by it at distances where nothing else about them is readable.

What He Cannot Do

He cannot make a hole.

Kestrels nest in cavities and have no ability to excavate one, so a pair depends entirely on somebody else’s work — an old woodpecker hole, a rotted-out limb, a gap under a barn eave. Or a nest box. And here is the lucky part: they take to boxes with real enthusiasm.

That matters, because American kestrel numbers have fallen substantially across North America. The causes are still argued over — loss of open ground, fewer large insects, fewer standing dead trees, and predation by the very accipiters that have thrived in the same landscapes. Cooper’s hawks do take kestrels, and the Cooper’s hawks in this collection are doing very well indeed. Two birds in the same city, on opposite ends of the same transaction.

Cavities are the one part of that list an individual can act on. A properly built and properly sited kestrel box on the edge of open ground is one of the few conservation gestures where a person can put up a thing and have a falcon move into it.

Where to Look

Open ground with something tall at the edge of it. Kestrels want a view of short grass and a place to sit above it — which describes field margins, fence lines, powerline corridors, airfields, and the mowed verges along almost any road out of town.

Scan the tops. Not the middle of a tree, not a branch inside cover — the highest exposed point available: the last inch of a wire, the peak of a pole, the topmost dead twig. That habit alone will find you more kestrels than any amount of walking.

A Closing Note on Rank

Medieval falconry lore assigned birds by station — the eagle to an emperor, the peregrine to a prince, the goshawk to a yeoman — and near the bottom of that list the kestrel was set aside for the servant. The knave’s bird.

The tidy hierarchy is more folklore than law, likely a literary flourish rather than anything anybody enforced. But it stuck, and it is a poor verdict. The kestrel simply had the bad luck to be small, common, and unimpressive to people who measured a falcon by what it could kill.

Four ounces. Two foveae in each eye. Sees ultraviolet. Hangs motionless in a crosswind. Lands on twigs that move. Go and look at the face at the top of this page and render your own judgment.

Quiz: Ten Questions on Kestrels