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
Miller Tern brakes and an optional tail-mounted drag chute. The cantilever wing uses a Wortmann 61 series airfoil. The basic Tern has a wingspan that gives a glide ratio of 34:1 at , while the longer span Tern II, with its wingspan, has a glide ratio several points higher. In March 2011 there were 14 Terns on the Federal Aviation Administration register, including 4 Tern IIs and one Tern 17M. All Terns are registered in the USA as "Experimental - Amateur-built" In March 2011 there were two Terns registered with Transport Canada, both amateur-builts. Miller Tern The Miller Tern is an American