Birds of prey (raptors) come in many shapes and sizes. When hawkwatchers identify birds of prey in flight, they look mainly at body shape, proportions, and flight characteristics. There are three general types of raptors recognizable by body and wing shape: buteos, accipiters and falcons. The shapes of these birds also indicate how they fly and, thus, their life-styles. The following silhouettes help identify these three basic groups of raptors.
These soaring hawks have long, broad wings and wide, fanned tails. Buteos are built to glide effortlessly on air currents. They can soar for long stretches without flapping their wings. Their soaring ability lets them hunt for prey while circling over open areas. They will perch on trees and utility poles and wait for unsuspecting prey to move below. Buteos include the Broad-winged Hawk, Red-tailed Hawk, Red-shouldered Hawk and Rough-legged Hawk.
With short, round wings, and long, rudder-like tails, accipiters are agile forest hawks. These birds, which are adept at maneuvering in thick woods, dart through trees, hunting birds on the wing. Although they sometimes soar like buteos, their typical flight pattern is several flaps followed by a glide. Cooper’s Hawks, Northern Goshawks and Sharp-shinned Hawks are examples of accipiters.
Falcons, the fastest birds of prey, are built for speed with streamlined bodies and long, pointed wings. Falcons most often flap continuously while in flight. The peregrine falcon can dive at speeds of over 150 miles per hour. Falcons often hunt other birds on the wing. The smallest falcon, the American kestrel, is able to hover in one place while hunting small rodents and insects. Falcons include the American Kestrel, Peregrine Falcon, and Merlin.
In all, 16 species of birds of prey commonly migrate over Hawk Mountain, nine of which fall into one of the three above categories. The six other birds of prey include Osprey, Bald Eagle, Golden Eagle, Northern Harrier, Turkey Vulture and Black Vulture.
The long narrow wings of Ospreys are often crooked at the wrist so that the leading edge of the wings forms an “M” shape. Underneath, Ospreys have contrasting dark and light plumage. Ospreys tend to glide extensively on migration. Ospreys hunt mainly for fish, and are seldom found far from water. In hunting, Ospreys plunge feet first into the water to capture fish swimming near the surface. The bottoms of Ospreys’ feet are rough like sandpaper, allowing them to grip their slippery prey.
The two eagle species - the Bald Eagle and Golden Eagle - are two of the largest birds of prey found in North America. The Bald Eagle is our national symbol. Adults have a white head and tail, and a dark body. The long, wide wings are held flat while soaring and the large head and beak are noticeable from a distance. Bald Eagles, which hunt live prey, mainly fish, are also scavengers. The Golden Eagle has a smaller head and beak and its wings often form a slight “V” when its gliding.
With wings held above the body in a shallow “V” these birds of prey with an “owl-shaped face” hunt over marshes, meadows and open fields. Northern Harriers, or marsh hawks, can be identified by a white rump patch at the base of their long narrow tails.
Turkey Vultures also hold their wings in a “V” or dihedral. They are easily identified by their rocking flight as they soar in circles taking advantage of rising thermal currents. Unlike most birds of prey, Turkey Vultures have a keen sense of smell, which helps them to find dead and rotting animals for food.
In the fall, hawks flying over Hawk Mountain are counted as they pass the Sanctuary’s North Lookout. The count has been conducted annually since 1934, and is a very valuable tool to study changes in raptor populations.