Prairie, meadow and swamp are generally agreed to be the typical breeding/foraging habitat of harriers. Bent 1937, Ehrlich et al 1988, Hamel 1992, Harrison 1975, Snyder & Snyder 1991. Johnsgard (1990) goes on to elaborate 'grasslands, marshy habitats, open-country, medium to tall prairie grasslands and associated wetlands, fresh and saltwater marshes, swamps and bogs, wet meadows, logged over or burned woodlands, open muskegs and tundra.' Ponds, lakes and slow moving streams that are bordered by 'lush growth', as well as cultivated fields (e.g. hay, wheat, rye, sugar beet, alfalfa, sweet clover ), and drier portions of estuaries, either brackish, fresh, or saltwater, that are grown to sedges, grasses, cattails or brush are often utilized. Palmer 1988

Johnsgards (1990) summized that although harrier lean toward wet habitats, dry nest sites are preferred. Brown and Amadon (1968) report that nests are built on the ground and 'often in marshy places and commonly in low shrubby vegetation, tall weeds or reeds rather than very open sites. Palmer (1988) has a similar report of nests on 'grassy ground, among low brush or close beside a bush or tree or in mixed herbaceous/woody growth in damp places and often near water.' Most literature reports the nest in some type of vegetation , i.e. grasses, sedges, willows, forbs, shrubs.

NATURE SERVE GLOBAL HABITAT COMMENTS:

BREEDING: Marshes, meadows, grasslands, and cultivated fields. Perches on ground or on stumps or posts. Nests on the ground, commonly near low shrubs, in tall weeds or reeds, sometimes in bog; or on top of low bush above water, or on knoll of dry ground, or on higher shrubby ground near water, or on dry marsh vegetation. Breeding habitat in the northeastern U.S. includes abandoned fields, upland maritime heaths, wet hayfields, salt marshes, and cattail marshes (Serrentino 1992).

In the Northeast, a wide range of open habitats and vegetative associations are used for breeding. Nests are placed on the ground, usually in dense cover. Nesting sites have included abandoned fields in dense stands of meadowsweet (SPIRAEA LATIFOLIA) or red-osier dogwood (CORNUS STOLONIFERA) in New Hampshire (Serrentino 1987), upland maritime heaths comprised of northern bayberry (MYRICA PENSYLVANICA), black huckleberry (GAYLUSSACIA BACCATA) and wild rose (ROSA spp.) in Massachusetts (Holt and Melvin 1986), and in wet hayfields dominated by reed canary grass (PHALARIS ARUNDINACEA) in Vermont (Laughlin and Kibbe 1985). Breeding sites in New Jersey saltmarshes on the Atlantic coast have been found in pure stands of common reed (PHRAGMITES AUSTRALIS), as well as in salt hay grass (SPARTINA PATENS) and smooth cordgrass (SPARTINA ALTERNIFLORA) (Dunne 1984).

On Long Island, nests were found in stands of common reed and poison ivy (TOXICODENDRON RADICANS) (England 1989). Other nesting habitats in the Northeast are cattail marshes (Laughlin and Kibbe 1985, Serrentino 1989), bogs (Hall 1983, Laughlin and Kibbe 1985, Andrle and Carroll 1988), native grassland prairies (Genoways and Brenner 1985), and dwarf conifer forest (England 1989). In other regions of North America, harriers nest in a variety of upland and wetland habitats such as willow (SALIX spp.) swales and meadows (Hamerstrom and Kopeny 1981), pure stands of blackberry (RUBUS spp.) (Toland 1985), hayfields and cropland (Duebbert and Lokemoen 1977, Follen 1986) and undisturbed grass/legume vegetation (Duebbert and Lokemoen 1977).

NON-BREEDING: In the Northeast, winter in the greatest numbers in the saltmarshes of the Atlantic coast, with the winter population exhibiting a tendency to increase from north to south (National Audubon Society 1971-74, 1982-83, 1985-87). Although harriers appear to prefer coastal regions in the Northeast, they will range inland during the winter when suitable open habitats are available (Root 1988), though avoiding the mountainous interior. Other habitats used by harriers during the nonbreeding season in both coastal and inland areas include agricultural fields (croplands, hayfields, and pastures), abandoned fields, and freshwater wetlands. Elsewhere in North America, wintering harriers have been observed in habitats similar to those in the Northeast (Craighead and Craighead 1956, Bildstein 1978, Temeles 1986, Collopy and Bildstein 1987, Littlefield and Thompson 1987). WINTER ROOSTS: Communal roosting flocks may be formed during the nonbreeding season, beginning in October and often breaking up at the onset of spring migration (Bildstein 1979). Harriers roost on the ground in open habitats such as agricultural and abandoned fields, and saltmarshes (Weller et al. 1955, Mumford and Danner 1974, Bildstein 1979, Evans 1982, Bosakowski 1983). The same roost may be used for several nights or for several months (Bent 1937, Craighead and Craighead 1956). The number of birds using roosts varies from several to 60 individuals, and roosts may be shared with short-eared owls (ASIO FLAMMEUS). Roost sites may be abandoned during periods of flooding or heavy snow (Bildstein 1979) or when prey becomes depleted in areas adjacent to roosts (Craighead and Craighead 1956, Bildstein 1979).

HUNTING HABITAT: Selection of hunting habitat is affected by several parameters including proximity to the nest site (Schipper 1977, Martin 1987, Serrentino 1987), sex and age of the individual (Schipper et al. 1975, Bildstein 1978, Marquiss 1980), prey abundance and availability (Schipper et al. 1975), vegetation structure (Schipper et al. 1975, Temeles 1986), and the presence of competitors (Temeles 1986). During the breeding season, females often hunt in areas adjacent to the nest site (Schipper 1977, Martin 1987, Serrentino 1987). Males hunt farther from the nest where they may encounter habitat types different than those located adjacent to nests.

Differences in habitat selection have been observed among adult females, adult males, and juveniles. In Ohio, intersexual differences in habitat selection were related to prey choice (Bildstein 1978). Females were observed significantly more often than males in fallow fields where small mammals were common. Adult males preferred corn stubble where avian prey was predominant. Males took more birds than females (40% vs. 4%), while females were principally small mammal specialists (93% for females versus 56% for males). Unsexed juveniles relied primarily on mammals.

Harriers select habitats on the basis of the availability and abundance of prey species. In the Netherlands, harriers preyed upon common voles (MICROTUS ARVALIS) in agricultural areas when voles were accessible and populations were high (Schipper et al. 1975). However, when voles became concealed by heavy snowfall, harriers hunted in reedbeds where avian prey was common.