Spectacled tern Spectacled tern The spectacled tern ("Onychoprion lunatus"), also known as the grey-backed tern, is a seabird in the family Laridae. A close relative of the bridled and sooty terns (with which it is sometimes confused), the spectacled tern is less common than the other members of its genus and it has been studied less. The three species, along with the Aleutian tern were recently split into a new genus "Onychoprion" from "Sterna" (Bridge "et al.", 2005). They resemble the sooty tern but with a grey back instead of a black one. Their breast and underparts are white, and they have
Sandwich tern and its underparts white, and this tern looks very pale in flight, although the primary flight feathers darken during the summer. The lesser crested tern and elegant tern differ in having all-orange bills; lesser crested also differs in having a grey rump and marginally stouter bill, and elegant in having a slightly longer, slenderer bill. Chinese crested tern is the most similar to Sandwich, but has a reversal of the bill colour, yellow with a black tip; it does not overlap in range with Sandwich tern so confusion is unlikely. In winter, the adult Sandwich tern's forehead becomes white. Juvenile