Ring-billed gull Larus delawarensis

Identification Tips:

• Medium-sized gull
• Fairly short, small bill with indistinct gonydeal angle

Adult alternate:

• Bright yellow bill with complete black ring at gonys
• Bright yellow legs
• Yellow eye
• White head, neck, breast and belly
• Pale gray back and upperwings
• White tertial crescent
• Black primaries with white tips and two white mirrors on outer primaries
• White tail

Adult basic:

• Like adult alternate but thin dark streaks about head and duller soft parts

Juvenile:

• Black bill quickly developing pale base
• Pale head, breast, back and belly with light brown scalloping
• Dark upperwing coverts with wide white edgings
• Pale belly
• Dark outer primaries
• Dark terminal band on white tail

First-year:

• Pink bill with black tip
• Pink or gray legs
• White head, neck and upper breast streaked with brown
• Pale gray back
• Upperwing coverts dull brown
• Pale gray secondaries
• Black primaries
• Dark terminal band on white tail

Second-year:

• Like adult basic but often with black-tipped yellow bill, entirely dark primaries and partial tail band

Similar species:

Adult Herring Gulls are similar to Ring-billed Gulls but are much larger, have pinkish legs, and a much thicker yellow bill with more pronounced gonys. First-winter Herring Gulls are much browner, but second and third-winter birds can be confusing since soft part colors are variable and third-year Herring Gull often show a ring around the bill. Such birds are most easily distinguished by the larger size and larger bill of Herring Gull. California Gulls are more similar in size and shape but are still larger and bigger-billed. Adults are darker-backed than Ring-billeds, with a brown eye, heavier head streaking, and a different bill pattern. Immatures are browner overall and show less contrast between the upperwing coverts and the secondaries. Adult Mew Gulls have unmarked bills, a darker gray back and are smaller. Juvenile Mew Gulls are much darker. First and second-winter Mew Gulls have a darker gray back and a daintier appearance. Common Black-headed and Bonaparte's Gulls are somewhat smaller in winter but have dark auriculars and very different wing markings in flight. Winter adult Black-legged Kittiwake has a plain yellow bill and entirely black wingtips.