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
Common tern cheeks more obvious, whereas the rump of the common tern can be greyish in non-breeding plumage, compared to the white of its relative. The common tern develops a dark wedge on the wings as the breeding season progresses, but the wings of Arctic stay white throughout the northern summer. All the flight feathers of the Arctic tern are translucent against a bright sky, only the four innermost wing feathers of the common tern share this property. The trailing edge of the outer flight feathers is a thin black line in the Arctic tern, but thicker and less defined in the