What do falcons eat

A Peregrine Falcon (Falco peregrinus) spots a Rock Pigeon crossing a park in lower Manhattan. It does not chase. It climbs - a slow, deliberate spiral - until it is three hundred feet above its target, then drops. The stoop lasts about three seconds. The pigeon does not survive.

That sequence explains more about falcon diets than any list of prey species. Falcons are aerial hunters first. What they eat follows directly from what they can intercept, which follows from how fast and how high they fly. The food varies considerably across the North American species. The physics stays the same.

The peregrine: 450 documented prey species

Cornell Lab’s All About Birds documents 450 North American bird species taken by peregrines, with the worldwide total potentially reaching 2,000. That figure reflects a hunter capable of taking anything from a hummingbird to a Sandhill Crane, and as elusive as a White-throated Swift.

Typical prey runs toward medium-sized birds: shorebirds, ducks, gulls, grebes, storm-petrels, pigeons, and songbirds including jays, thrushes, waxwings, and starlings. Coastal birds shift toward waterfowl. Urban peregrines eat pigeons almost exclusively, which is why cities now hold stable breeding populations - the food supply never runs out.

Bats appear regularly in the diet. Peregrines also pirate prey from other raptors when the opportunity presents - stealing a fish or rodent from an osprey takes less energy than hunting one. The kill method is consistent: stoop to strike or grab the bird mid-air, then bite through the neck to finish it.

A peregrine’s diet is not about preference. It is about what flies across the airspace the bird already controls.

Speed is the tool. The National Park Service reports dive speeds exceeding 200 miles per hour, making the peregrine the fastest animal on the planet in a stoop. That speed requires altitude to generate, and altitude takes time. The hunt is slow to set up and instant to resolve.

How the other species divide the menu

The American Kestrel (Falco sparverius) sits at the opposite end of the falcon spectrum. Audubon’s field guide lists grasshoppers as the primary prey, with beetles, dragonflies, moths, and caterpillars filling out the insect column. When insects thin out, the kestrel shifts to small mammals - voles, mice, occasionally bats - and small birds up to the size of a quail. Individuals often specialise on one prey type and stay with it. A kestrel hovering over a highway median is hunting the same grasshoppers it found there the day before.

The Merlin (Falco columbarius) sits between the kestrel and the peregrine in size and appetite. Audubon documents a diet dominated by small birds - Horned Larks on the plains, House Sparrows in towns, small sandpipers on the coast - caught in direct aerial pursuit rather than from a stoop. The prey list shifts with the seasons, because the bird itself moves. Merlins add dragonflies, rodents, and bats as supplements. What they rarely do is dive steeply from height, which marks their technique clearly apart from the peregrine’s.

The Prairie Falcon (Falco mexicanus) is the most seasonally flexible North American species. Audubon’s field guide describes an early-summer diet heavy in ground squirrels, shifting to newly fledged songbirds in late summer when they are vulnerable, then concentrating on flocking Horned Larks through winter. Low, fast passes over open ground suit prey that walks or runs rather than prey that flies high. Grouse and jackrabbits appear in the diet, along with lizards and insects. Audubon notes the bird tends to focus on one abundant and easily caught prey species at a time.

The Gyrfalcon (Falco rusticolus) feeds on the largest prey of any North American falcon. Audubon documents ptarmigan as the dietary staple on Arctic tundra. Coastal populations take greater proportions of gulls, ducks, and geese. Wintering birds in western North America have been recorded taking Greater Sage-Grouse. Lemmings, ground squirrels, and hares supplement the diet when birds are scarce.

The pattern underneath the variety

The differences across these species follow a single logic. Larger falcons with longer wingspans take larger prey and rely on speed or sustained pursuit. Smaller falcons hunt smaller prey using hovering or low-level ambush. What no North American falcon does, as a rule, is scavenge carrion or forage for seeds on the ground. They are built for flight and they hunt accordingly.

The peregrine’s DDT-driven collapse in the mid-twentieth century demonstrated how tightly falcon diets bind the bird to its prey base. Organochlorine pesticides moved up the food chain through the birds peregrines hunted. The falcons concentrated the toxins in their eggs, the shells thinned, and breeding failed across North America. The species was listed as endangered in 1973 and removed from the Endangered Species List in 1999, after DDT was banned and captive breeding programmes restored pairs to historical ranges.

The peregrine came back because the pigeons and shorebirds it depended on came back. The menu preceded the hunter’s recovery. It always does.

Falconers who keep these birds for sport know the diet question intimately - feeding a captive falcon requires matching prey to species, since a kestrel’s digestive system is calibrated to insects and small rodents in a way that a gyrfalcon’s is not. Wild birds solve the problem automatically through habitat selection. The kestrel that cleans a hummingbird feeder off a suburban porch is not the bird you expect to see, because kestrels and hummingbirds don’t share hunting grounds - one is hovering for grasshoppers while the other is hovering for nectar, same physics, entirely different purpose.

What separates falcons from every other bird family in the order Falconiformes is not simply diet. It is the relationship between diet and technique - each species locked into a prey type the way the Northern Cardinal is locked into seeds, shaped by a bill that cannot do anything but what it evolved to do. The peregrine’s tomial tooth notch at the tip of the upper mandible severs the spinal cord of the prey it catches. No hawk has one. No eagle has one. It is a precision instrument, and the 450 species on the peregrine’s prey list represent two thousand years of that instrument finding new uses.