Sterna

Sterna is a genus of terns in the bird family Laridae, comprising 13 species of typical medium-sized white terns with deeply forked tails, established by Carl Linnaeus in 1758 with the common tern as its type species. The genus was formerly defined much more broadly until genetic research showed the old classification was paraphyletic and narrowed it to its current membership. Species occur near-globally, mostly in coastal regions but several also inland on fresh water, ranging from the Arctic tern polar range to the South American tern and the Antarctic tern.