The Killdeer is by far the most wide-spread and familiar of North American plovers because of the habitats it frequents, its tolerance of humans, its easily observed and often anthropomorphized parental care, and its killdeer vocalizations. Earlier common names, such as Chattering Plover (Catesby 1731) and Noisy Plover (Latham 1785), described the very vocal nature of this species. Once the target of market hunters and in serious decline, the Killdeer is probably more common today than at any time in its history as a result of habitat changes wrought by humans. At the same time, the species is vulnerable to twentieth-century problems such as pesticides, oil pollution, lawnmowers, and automobiles. Breeding Bird Surveys suggest that it is declining in some western states.
Although technically shorebirds, Killdeer are often found away from shores as well as near them, frequenting mudflats, gravel bars, short-grass meadows, and their twentieth-century counterparts, such as construction sites, road shoulders, gravel roads and driveways, graveled rooftops, lawns, pastures, and golf courses. They are most often found near water of some sort, even if it is a lawn sprinkler. Their long legs and running-stopping-bobbing gait are co-nspicuous, but not nearly so attention-getting as the broken-wing act and piteous cries they indulge in to draw potential predators away from nests and chicks.
Nesting begins in early spring—March in the Deep South, April in the middle states, May in the northern tier of states and southern Canada, and June in the far north. In the Caribbean, Killdeer will nest year-round. A disjunct breeding population of Killdeer in coastal Peru and northwestern Chile breeds at least in January and June.
Long, pointed wings allow rapid flight and quick maneuvers. Northern populations are migratory, southern ones resident. The Killdeer is active both day and night and can often be heard calling overhead in the darkness, especially in early spring and late summer. Mall parking lots and lighted ball fields seem to be attractive for nocturnal activities, which include a great deal of socializing, calling, and foraging.
As common a bird as the Killdeer is, there have been few in-depth studies of its behavioral ecology, and most of those have been theses or dissertations. Most detailed studies have dealt with behavioral ecology associated with nesting (e.g., in Minnesota, Mace 1971, Lenington and Mace 1975, Lenington 1980, and Brunton Brunton 1988a, Brunton 1988b, Brunton 1990; in Michigan, Bunni 1959; in Oregon, Cronan 1974; in Mississippi, Schardien 1981; in Utah, Mundahl 1982; in Ontario, Nol 1980 and Nol and Lambert 1984; and in Manitoba, Phillips 1972 . Other topics studied in depth include vocalizations (Bursian 1971) and social organization of a wintering population (Heck 1985 in North Carolina). Most other studies were limited and often anecdotal. Townsend (Townsend 1929) provided an earlier literature review.