The sooty tern is about 16 inches long with a white forehead & is otherwise this color above & white below
This bird is blackish above and entirely white below, including the sides of the ..... 
Terns are birds of similar plumage to the Gulls, but their forms are less ..... A 
beautiful Gull, 16 inches long, with a dark slate colored head, gray... [DOC] [TLE] Identifying Similar Species - Welcome to Potomac Wildlife!