Least Tern Identification

Adult Description

Small tern. During breeding, black cap ending at white forehead. Short white eyestripe. Bill yellow with black tip. Back light gray. Underside white. Black leading edge to wing. In nonbreeding plumage has black eyestripe extending to back of head, white top of head, and black bill.

Immature Description

Juvenile with U-shaped marks across back. Immature resembles winter adult.
Relative Size

Relative Sizebetween robin and crowbetween robin and crow
Measurements
  • Both Sexes
    • Length: 8.3-9.1 in (21-23 cm)
    • Weight: 1.1-1.6 oz (30-45 g)
    • Wingspan: 18.9-20.9 in (48-53 cm)