A common hawk often seen flying slowly over open areas as it hunts, the northern harrier is easily identified by its conspicuous white rump and owl-like facial disk. This is an unusual raptor in that males and females are dimorphic with distinctly different colors and markings, but both sport the white rump and facial disk field marks that are diagnostic for proper identification.
Northern Harrier, Marsh Hawk, Hen Harrier
- Bill: Black with pale yellow cere, short, strongly hooked
- Size: 16-25 inches long with 40-45-inch wingspan, long tail, slim build, long wings
- Colors: Gray, white, yellow, black, brown, buff, orange-buff
- Markings: Dimorphic species. Males have a gray face and hood accented by an owl-like facial disk and a white eyebrow. The back and upperparts are gray, and the wings are gray with black tips and a black trailing edge. The rump and uppertail coverts are bright white, and the underparts are also white with sparse brown streaks or spotting. The tail is gray with thin brown or blackish bars. Females are larger than males and have brown plumage heavily barred under the wings with a dark trailing edge seen in flight. The underparts are pale buff or white with brown streaking, and the brown tail has dark bars. Like males, females also have the facial disk and indistinct white eyebrow. Both genders have yellow eyes and yellow legs and feet.
Juveniles are similar to adult females but have less streaking and a richer orange-buff color on the underparts, though depending on the subspecies they can be almost indistinguishable from adult females.
Habitat and Migration:
These agile hawks prefer open, flat habitats such as either freshwater or brackish marshes, wetlands, farmland, prairie, steppe and tundra. Northern harriers are found year-round in North America in the northern United States from California to Virginia, and in Europe from the United Kingdom to France, northern Spain and elsewhere in isolated pockets in western Europe.
In summer, the northern harrier expands its breeding range to cover western Canada and Alaska as well as northern Europe. In winter, these raptors migrate to the southern United States and Mexico through Central America and as far as Venezuela, while some populations winter in Cuba and the Bahamas. In Europe, their winter range extends through southern Europe to the Middle East.
Northern harriers are quite vocal for diurnal raptors and have a high "kee-kee-kee" call, similar to a sharp gull's call but with shorter, more piercing notes. When defending the nest, they will use a high scream with a descending pitch.
These raptors hunt low over open fields, often gliding or hovering briefly while they scan for prey. They have exceptional hearing, concentrated by their unique facial disk, and often locate prey as much by sound as by sight. When gliding, the northern harrier holds its wings in a shallow-V shape, which can help to identify the bird if it is viewed from the proper angle.
These raptors are occasionally polygamous, particularly when food supplies are abundant, and the males use an acrobatic courtship flight to attract females. A mated pair works together to build a shallow platform nest of sticks and grass, positioned either on the ground or up to five feet high. When laid, the eggs are whitish or pale blue-white, occasionally sparsely scattered with dark spots. There are 2-10 eggs per brood, and only one brood is laid per year.
Attracting Northern Harriers:
While these raptors are not typical backyard visitors, they may appear in backyards near open areas where the habitat is suitable. Avoiding trapping or poisoning rodents can help provide a suitable food source for northern harriers, and insecticide use should be minimized as well since they will also feed on large insects.
Northern harriers are not considered threatened or endangered, though in the past they were frequently shot by farmers and hunters alike. Today they suffer from habitat loss as marshes are drained for agriculture or development. Insecticide use and poisoning rodents can also impact northern harrier populations, and numbers of these raptors are slightly declining in many areas but those population changes are not yet severe enough to warrant ongoing concern.