In North America the Sandwich Tern (Thalasseus sandvicensis) breeds locally along marine coasts and offshore islands primarily of the southeastern United States and Caribbean (AOU 1998). In these areas it commonly nests in dense colonies of the Royal Tern (T. maximus) and Laughing Gull (Leucophaeus atricilla; Shealer 1999). It winters along the coasts of the Atlantic Ocean and Gulf of Mexico from Florida to the West Indies, more rarely as far south as southern Brazil and Uruguay. It also winters on the Pacific coast, mainly from Oaxaca, Mexico, south to Panama (Howell and Webb 1995), occasionally to Colombia, Ecuador, and Peru (AOU 1998). As there are no breeding colonies on the Pacific coast, all birds wintering there are believed to represent migrants from Atlantic and Caribbean colonies (Collins 1997, Hilty and Brown 1986, Ridgely 1981, Ridgely and Greenfield 2001). Sandwich Terns have occasionally wandered as far north as eastern Canada (New Brunswick, Nova Scotia, and Newfoundland) and inland to Minnesota, Michigan, and Illinois (AOU 1998, Clapp et al. 1983). In the Pacific, vagrants are known from California and the Hawaiian Islands (Hamilton et al. 2007, AOU 1998).