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NORTHERN HARRIER <br /> (Circus cyaneus) <br /> STATUS <br /> Federal: None <br /> State: Species of Special Concern <br /> Other: CNDDB Special Animal <br /> DESCRIPTION <br /> Northern harriers are slim-bodied raptors with long, narrow wings and an owl- <br /> like facial disk. Adult harriers are 17 to 23 inches long and have wing spans <br /> from 38 to 48 inches. This species flies with its wings upraised in a <br /> characteristic dihedral position. Harriers are sexually dimorphic in plumage. <br /> Males are gray and females are brown, but both sexes have a characteristic <br /> white rump. <br /> DISTRIBUTION <br /> The breeding range of northern harriers extends from the southern United <br /> States, Mexico and northern Baja California to northern Alaska and Canada. <br /> Harriers winter from southern Canada to northern South America (Evans, <br /> 1982). <br /> In California northern harriers are permanent residents. The Central Valley <br /> supports a large population of this species that breeds, forages and winters in <br /> grassland habitats and open fields adjacent to the major rivers and drainages. <br /> The breeding season extends from mid-April through August (McCaskie, De <br /> Benedictis,Erickson and Morlan,1979). <br /> HABITAT PREFERENCES <br /> Non-forested habitat types such as grasslands, marshes and prairies are <br /> utilized for nest sites and foraging grounds by northern harriers. The nests are <br /> typically located on the ground in a marsh or tall grass. In the winter harriers <br /> sometimes roost communally. These communal roosts are located on the ground <br /> in relatively undisturbed marshes or fields (Evans, 1982). In the nonbreeding <br /> season females aggressively exclude males from preferred feeding areas <br /> (Ehrlich et al., 1988). This suggests that there is some sort of resource <br /> partitioning during the nonbreeding season to limit intraspecific competition <br /> between sexes. <br /> FORAGING HABITS <br /> Northern harriers hunt for their prey while flying low over open fields and <br /> grassland habitats. This species is unique among raptors in its utilization of <br /> acoustical sensory location of concealed prey items (Rice, 1982). Prey species <br /> include small mammals, birds, reptiles, arthropods, carrion and fish (Ehrlich <br /> et al., 1988). The most important prey species in many areas is the vole <br />