The Black Skimmer, one of North America's most distinctive coastal waterbirds, is noted for its unusual voice, bill, and feeding behavior. Its bill—brightly colored, laterally compressed, and knife-like, with the lower mandible extending beyond the maxilla—is uniquely adapted to catch small fish in shallow water. A feeding skimmer flies low over the water with its bill open and its lower mandible slicing the surface. When the mandible touches a fish, the upper bill (maxilla) snaps down instantly to catch it. The buoyant flight of this bird, coupled with its dog-like barks, prompted R. C. Murphy ( Murphy 1936 ) to describe Black Skimmers as “unworldly…aerial beagles hot on the scent of aerial rabbits.”
Skimmers are highly social birds, nesting in colonies and forming large flocks outside the breeding season. Large, successful colonies usually occupy the same site from year to year, while small or failed colonies usually relocate. Neither nest site limitation nor enhanced sharing of information about food appear to account for skimmer coloniality. Over most of its range, this species nests in colonies with various species of terns, deriving some protection from these aggressive neighbors. Although skimmers are active throughout the day, they are largely crepuscular and even nocturnal; their tactile feeding lets them catch fish successfully in low light or darkness.
Three races of Black Skimmer inhabit North and South America. The North American race (R. n. niger) is almost entirely coastal, while the South American races (R. n. cinerascens and R. n. intercedens), as well as the Indian Skimmer (R. albicollis) and the African Skimmer (R. flavirostris), nest mainly on riverine sandbars.
This account focuses almost exclusively on North American populations of the Black Skimmer; see Murphy ( Murphy 1936 ) for details on the South American races. Burger and Gochfeld ( Burger and Gochfeld 1990b ) should be consulted for more extensive data on breeding biology in New York and New Jersey, Clapp et al. ( Clapp et al. 1983c ) for additional details on distribution.
Other names for this species are: Scissor-bill, Shearwater, Seadog (Virginia) ( Howell 1911a ), Flood Gull, Stormgull ( Pearson 1936 ), Razorbill ( Murphy 1936 , Kale II and Maehr 1990 ), and Cutwater ( Nuttall 1903 , Eaton 1910 ).