Northern Harrier

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Image:NoHarrier.jpg

Common Name: Northern or Hen Harrier
Scientific Name: Circus cyaneus

Size: 16-20 inches (41-52 cm); Wingspan: 38-48 inches (97-122 cm)

Habitat: North America and Eurasia; breeds throughout the northern parts of the northern hemisphere in Canada and the northernmost USA, and in northern Eurasia. It migrates to more southerly areas in winter. Eurasian birds move to southern Europe and southern temperate Asia, and American breeders to the southernmost USA, Mexico, and Central America. In the mildest regions, such as France, Great Britain, and the southern US, harriers may be present all year, but the higher ground is largely deserted in winter. Northern Harriers breed in wide-open habitats ranging from Arctic tundra to prairie grasslands to fields and marshes. They breed on moorland, bogs, prairies, farmland coastal prairies, marshes, grasslands, swamps and other assorted open areas.

Status: Least Concern. Global population: 1,400,000 adult individuals. Northern Harriers are fairly common, but their populations are declining. The North American Breeding Bird Survey records a steady decline of 0.8 percent per year from 1966 to 2010, resulting in a cumulative loss of 30 percent, with Canadian populations declining more than U.S. populations. Partners in Flight estimates that 35% of the population spends some part of the year in the U.S., 17% in Canada, and 10% in Mexico. They rate an 11 out of 20 on the Continental Concern Score and are not on the 2012 Watch List. Habitat loss has contributed to reduced harrier populations as people have drained wetlands, developed land for large-scale agriculture, and allowed old farmland to become reforested. The small mammals that harriers prey upon have been reduced because of overgrazing, pesticides, and reduced shrub cover from crop field expansion. Because they eat small mammals, Northern Harriers are susceptible to the effects of pesticide buildup as well as direct effects by eating poisoned animals. In the mid-twentieth century their populations declined from contamination by DDT and other organochlorine pesticides, but rebounded after DDT restrictions went into effect in the 1970s. Northern Harriers have been mostly safe from hunting because of their reputation for keeping mouse populations in check, but they are still sometimes shot at communal winter roosts in Texas and the southeastern United States.

Diet: Small mammals (voles, cotton rats and ground squirrels), small birds (mostly hunted by male harriers) and occasionally are amphibians (especially frogs), reptiles and insects (especially orthopterans). Larger prey, such as rabbits and adult ducks are taken sometimes and subdued these by drowning them underwater.

Harriers use hearing regularly to find prey-- they have exceptionally good hearing for diurnal raptors. Northern Harriers fly low over the ground when hunting, weaving back and forth over fields and marshes as they watch and listen for small animals. They eat on the ground, and they perch on low posts or trees.

Nesting: The male of the nominate race, C. c. cyaneus which breeds in Europe and Asia, is mainly grey above and white below except for the upper breast, which is grey like the upperparts, and the rump, which is white; the wings are grey with black wingtips. The female is brown above with white upper tail coverts, hence females, and the similar juveniles, are often called "ringtails". Their underparts are buff streaked with brown.

The male of the race, C. c. hudsonius, which breeds in North America, plumage is darker grey than that of C. c. cyaneus and the female is also darker and more rufous. Juvenile males have pale greenish-yellow eyes, while juvenile females have dark chocolate brown eyes. The eye color of both sexes changes gradually to lemon yellow by the time they reach adulthood.

Northern Harriers are the only hawk-like bird known to practice polygyny – one male mates with several females. Up to five females have been known to mate with one male in a season. Males perform elaborate flying barrel rolls to court females.

The nest is built on the ground or on a mound of dirt or vegetation. Nests are made of sticks and are lined inside with grass and leaves. Four to eight whitish eggs are laid. When incubating eggs, the female sits on the nest while the male hunts and brings food to her and the chicks. The eggs are incubated mostly by the female for 31 to 32 days. The male will help feed chicks after they hatch, but won’t usually watch them for a greater period of time than around 5 minutes. The male usually passes off food to the female, which she then feeds to the young, although later the female will capture food and simply drop into the nest for her nestlings to eat. The chicks fledge at around 36 days old.

Cool Facts: In some parts of Europe people believed that seeing a harrier perched on a house was a sign that three people would die; on a happier note, some Native American tribes believe that seeing a hawk on your wedding day is a sign of a long, happy marriage. Unlike many raptors, harriers have historically been favorably regarded by farmers because they eat predators of quail eggs and mice that damage crops. Harriers are sometimes called "good hawks" because they pose no threat to poultry as some hawks do. Heavy pesticide use in the 1970s and 1980s caused a decline in harrier populations.

Northern Harrier fossils dating from 11,000 to 40,000 years ago have been unearthed in northern Mexico.


This 3D model is found in Songbird ReMix Birds of Prey Volume III: Hawks of the New World

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