Habitat

Almost exclusively coastal, except for inland lakes such as Salton Sea, CA, and in Palm Beach Co., FL. Prefers open sandy areas or gravel or shell bars with sparse vegetation or broad mats of seawrack (dead vegetation) on salt marsh. Strongly selects colony sites based on the presence of other species, especially terns, that provide early warning and/or defense against intruders (Erwin 1979, 1980, Burger and Gochfeld 1990).

Much formerly suitable beach habitat no longer available due to commercial, residential, or recreational development (see Conservation and Management). Even island habitats subject to recreational pressures; in New York and New Jersey, species increasingly relegated to salt marsh islands, although less so elsewhere (M. Erwin pers. comm.). Occupancy of highest beaches by gull colonies discourages settlement by terns and skimmers (Burger and Gochfeld 1990). High interdune colonies such as Cedar Beach, NY, not vulnerable to flooding, but in New Jersey species often resorts to low-lying beaches remote from human disturbance and vulnerable to flooding (Burger and Gochfeld 1990). In N. Carolina, up to 90% of nests are on man-made or altered sites (e.g., dredge spoil islands) (Parnell and Soots 1980). In Florida, nests mainly on natural sandy or on dredge spoil islands and on berms along highways (Schreiber and Schreiber 1978); occasionally on gravel roofs (Greene and Kale 1976, Fisk 1978, Gore 1987). Most Gulf Coast colonies on barrier beaches, but 19% on shell berms in salt marsh (Clapp et al. 1983). At Salton Sea, nests in the high-water line of debris (McCaskie et al. 1974). See also Food Habits: microhabitat for foraging.

Little information; flocks rest on coastal beaches; occasional inland. South American riverine populations may move to coastal estuaries after breeding (Murphy 1936).

Coastal beaches, sand or shell bars in estuaries. Occasionally on beaches of inland lakes.