The South American Tern (Sterna hirundinacea) is a species of tern found in coastal regions of southern South America, including the Falkland Islands, ranging north to Peru (Pacific coast) and Brazil (Atlantic coast). It is generally the commonest tern in its range. It closely resembles the smaller, highly migratory Common Tern.
References
BirdLife International 2004. . Downloaded on 24 July 2007.