Location in Oregon
Red is Summer range

Forster's Tern

Sterna forsteri - Common in fresh and salt marshes, rare on coastal beaches. Strongly resembles Common Tern, but primaries are lighter than rest of wing, tail is pale gray with white outer margin (reversed in the Common), bill and legs are more orange, and wing stroke is faster and shallower. Winter birds are best told from the other terns by the narrow black eye patch. Feeds on insects as well as fish. Call, a low toneless zrurrr.