Falcon vs Hawk: Differences in Wings, Speed and Prey

Key differences at a glance

Falcons and hawks are both birds of prey with hooked bills, sharp talons and superb eyesight, so it is easy to think of them as close cousins. In fact they belong to separate families and even separate orders:

• Falcons (family Falconidae, about 65 species) include the peregrine falcon, gyrfalcon, merlin, kestrels, hobbies and the caracaras of the Americas.
• Hawks (family Accipitridae, about 250 species) include buteos such as the red-tailed hawk, accipiters such as Cooper’s hawk and the Eurasian sparrowhawk, and also eagles, kites, harriers and Old World vultures.

The table at the top of this page sums up the main differences. The sections below explain each one.

Wings and flight: pointed vs rounded

Wing shape is the best field mark. A falcon’s wings are long, narrow and come to a sharp point, like a swept-back blade. This shape reduces drag and suits fast, powered flight and steep dives. Falcons fly with quick, stiff, rowing wingbeats and rarely soar for long.

Hawks have broader wings. Buteos such as the red-tail have wide wings with spread, finger-like primary feathers at the tips, ideal for circling slowly on thermals while scanning the ground. Accipiters such as Cooper’s hawk have short, rounded wings and long tails for quick bursts and sharp turns through woodland, often flying with a “flap-flap-glide” rhythm. Kestrels, which are small falcons, can hover in one spot, and some hawks can hang in the wind too, but the overall outline still differs.

Bill and killing method

Look closely at a falcon’s bill and you will see a small, sharp notch on each side of the upper mandible, called the tomial tooth, with a matching dip in the lower bill. Falcons use it to bite through the neck of their prey and quickly sever the spinal cord. It is not a real tooth, since no living bird has teeth; see do birds have teeth?.

Hawks lack this notch. Their bill is a smooth hook used for tearing food apart. Instead, hawks kill with their feet: powerful toes and long, curved talons grip prey and squeeze until it dies. A falcon’s feet are used more as weapons for striking and grasping prey in flight.

Falcons also tend to have dark brown eyes ringed with bare yellow skin, and many species have a dark “moustache” stripe below the eye. Adult accipiters often have yellow, orange or red eyes, though adult red-tailed hawks have brown eyes.

Family tree: why falcons are closer to parrots

For most of the 20th century falcons were classified together with hawks and eagles in the order Falconiformes, because they look and behave so similarly. That changed with large DNA studies. In 2008, a major genomic study led by Shannon Hackett, published in Science, found that falcons are most closely related to parrots and passerines (songbirds), while hawks and eagles belong to a separate branch that also includes the osprey and secretary bird.

Today most authorities place falcons in their own order, Falconiformes, and hawks and eagles in Accipitriformes. Their sharp bills, talons and keen eyes are an example of convergent evolution: two unrelated groups evolving similar tools because they live similar predatory lives.

Speed and hunting style

Falcons are built for speed. The peregrine falcon hunts birds in open air, diving in a stoop at more than 300 km/h (186 mph) and striking prey in midair; see how fast can a peregrine falcon fly?. Smaller falcons such as merlins chase small birds in fast, low pursuit, while kestrels hover over fields to drop onto voles and large insects.

Hawks rely more on patience or surprise. Red-tailed hawks usually sit on a perch or circle high on thermals, then glide down onto rodents and rabbits on the ground, reaching about 190 km/h (120 mph) in a steep dive. Accipiters ambush songbirds from cover, dashing through trees and hedges. In general, falcons catch more of their prey in the air and hawks more on the ground or among branches.

Nests: scrape vs stick nest

Falcons do not build nests. Peregrines lay their eggs in a bare scrape on a cliff or building ledge, kestrels use tree holes and nest boxes, and many falcons take over the old stick nests of crows, ravens or hawks.

Hawks build their own nests from sticks and twigs, usually high in a tree, and line them with bark, leaves or fresh greenery. Red-tailed hawk nests can reach nearly 1 m (3 ft) across and are often reused and enlarged year after year.

Which is bigger and stronger?

There is a lot of overlap. Falcons range from falconets of about 35 g (1.2 oz) to the gyrfalcon, whose largest females weigh well over 1.5 kg (3.3 lb). Hawks range from the smallest accipiters, which weigh under 100 g (3.5 oz), to large buteos and goshawks weighing well over 1 kg (2.2 lb). Comparing the two best-known North American examples:

The red-tail is usually heavier and broader-winged, with stronger feet for gripping mammals. The peregrine is faster and more agile in the air. In both groups, females are larger than males.

Confusing names

Common names do not always follow the science. Old American names such as “duck hawk” (peregrine), “pigeon hawk” (merlin) and “sparrow hawk” (American kestrel) were all given to falcons. In Britain, “hawk” usually means an accipiter such as the sparrowhawk or goshawk, while buteos like the red-tail’s European cousin are called buzzards; see birds of prey in the UK. And nighthawks are not birds of prey at all, but insect-eating relatives of nightjars.

Falcons and hawks cannot interbreed, because they belong to lineages that separated tens of millions of years ago.