Habitat

High arctic to mid-latitudes and offshore islands in North America. Almost always associated with open country supporting cyclic small mammals (voles, lemmings), typically large expanses of prairie and coastal grasslands, heathlands, shrub-steppe, and tundra. Also agricultural areas. Nests usually located on dry sites with enough vegetation to conceal incubating female.

On Great Plains, prefers to nest within large patches of relatively tall (30 to 60 cm), dense, ungrazed grassland (Duebbert and Lokemoen 1977, Fondell and Ball 2004). In Illinois (Herkert et al. 1999), likewise requires relatively short grass (<50 cm tall); most diel grasslands in the region need to be mowed or burned to maintain this. Nests on the arctic plain typically on elevated patches of tundra vegetation (Pitelka et al. 1955a). At Churchill, Manitoba, often at base of small birch or willow (Jehl 2004). Nests in coastal Massachusetts in grassy dune vegetation (Holt 1992).

In Cuba (Garrido 1984 and pers. comm.), nests in pasturelands, rice fields, and sugar-cane plantations.  In Hispaniola (Guerrero 2005), one nest found in an abandoned agricultural field, below a small bush.

Will nest on slight ridges, mounds if present. In Europe, known to nest in moorlands, marshes, bogs, newly cleared forests, and within young evergreen plantations (Mikkola 1983, Cramp 1985, Voous 1988 8). See also Breeding: nest site.

Similar to breeding range, but also smaller open areas, if prey is available.

Similar to breeding habitat, but may use large open areas within woodlots, stubble fields, fresh and saltwater marshes, weedy fields, dumps, gravel pits, rock quarries, and shrub thickets (Clark 1975). In Missouri, prefers dense grasslands less than 30 cm high (Weller et al. 1955). Occasionally roosts in trees during winter (Clark 1975, Bosakowski 1986: see Behavior: sleeping and roosting). Winter areas often turn into breeding areas if food is plentiful (Clark 1975). In coastal se. Massachusetts, hunts salt marsh and (especially) salt marsh edge, where grass gives way to low brush (Iva sp.); also nearby open pastures and fields with low woody vegetation (Rosa, Prunus sp.; A. Poole).