The royal tern (Thalasseus maximus) is a seabird in the tern family Sternidae. This bird has two distinctive subspecies: T. m. maximus which lives on the Atlantic and Pacific coasts of the North and South America, and the slightly smaller T. m. albididorsalis lives on the coast of West Africa. The royal tern has a red-orange bill and a black cap during the breeding season, but in the winter the cap becomes patchy.