Bonaparte's Gull Identification

Adult Description

  • Small gull.
  • White triangle in outer part of wing.
  • Back pale gray.
  • Underparts white.
  • Head black during breeding.
  • Dark spot behind eyes in winter.

Immature Description

Juvenile with much brown on head, neck, and back, a dark bar across the wing, and a black tail tip. Immature similar to nonbreeding adult, but with brownish black bar across the base of the wing, much black in the outer wing, and a black band across the tip of the tail. In first breeding plumage the black head is partly mottled with white.
Relative Size

Relative Sizecrow sizedcrow-sized
Measurements
  • Both Sexes
    • Length: 11.0-15.0 in (28-38 cm)
    • Weight: 6.3-7.9 oz (180-225 g)
    • Wingspan: 29.9-31.5 in (76-80 cm)