The sooty tern is about 16 inches long with a white forehead & is otherwise this color above & white below
The Sooty Tern has black upperparts, cap, nape, eye-line; white 
forehead; white... [DOC] [TLE] Memoirs of the Bernice Pauahi Bishop Museum of Polynesian ... [PAR] 9305: Length 25.50. culmcn 2.00= tai16.5o, tarsus 2.85, ... 011s elongated white 
patch both above and below the eye; lower parts white ... above, darkest on the 
upper wing coverts; outer tail feathers almost as sooty black as ... Grey-backed 
Tern.