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
Sooty tern birds from Indonesia to the Americas: This is a large tern, similar in size to the Sandwich tern ("Thalasseus sandvicensis") at long with an wingspan. The wings and deeply forked tail are long, and it has dark black upperparts and white underparts. It has black legs and bill. The average life span is 32 years. Juvenile Sooty Terns are scaly grey above and below. The Sooty Tern is unlikely to be confused with any tern apart from the similarly dark-backed but smaller bridled tern ("O. anaethetus"). It is darker-backed than that species, and has a broader white forehead and no