Bonaparte's gull Larus philadelphia

Identification Tips:

• Small, tern-like gull
• Short, thin, black bill
• Adult plumage reached in second year

Adult alternate:

• Black head
• Very narrow white crescents above and below eye
• White neck, breast, belly, and tail
• Pale gray back and upperwings
• Pale scapular crescent and tertial crescent
• White wedge on outer primaries
• Black tips to primaries creates black trailing edge to primaries and black wingtips at rest
• Pale underwing and underside of primaries

Adult basic:

• Like adult alternate except lacks black hood and instead has black spot on ear coverts

Juvenile/First year:

• Juvenile strongly washed with brown which fades rapidly with wear
• Head and body like adult basic
• White tail with black terminal band
• Pale gray upperwing marked by dark carpal bar, dark trailing edge and slight white wedge in outer primaries

Similar species:

Adult Little Gulls have no black on the uppersurface of the wings and have wholly dark underwings. First-year Little Gulls are easily distinguished by the pale trailing edge to the wing, but also have wider, bolder carpal bars. Black-headed Gulls are superficially similar but have pale bills in all plumages and dark undersufaces to the primaries. Laughing and Franklin's Gulls both have much darker gray backs, never show similar wing patterns and have much thicker, more robust bills