RING-BILLED GULL
Ring-billed Gulls are three-year gulls, that is, they achieve adult plumage in their third year of life. All pictured birds were photographed in Redding, California, during the non-breeding season.

[Sibley, p. 214; National Geographic, 4th Ed., p. 198, 199 & 212]


ring-billed gull

The bird on the left is an adult Ring-billed Gull, and the one on the right is a first cycle immature. The middle gull does not appear to be a full adult because its A-spots (apical spots - the white tips on the primaries) are not fully developed, and the basal half of the bill is flesh colored, which is inconsistent with an adult bird. The middle bird is most likely a second cycle Ring-billed Gull.


First Cycle
ring-billed gull

A first cycle bird in winter plumage. Note the mantle, scapulars, and greater wing coverts are gray, while the median wing coverts are checkered in brown and white. The bill is flesh colored with a black tip; the eyes are dark.
ring-billed gull

Here is a view of a first cycle bird in flight.


Second Cycle
ring-billed gull

The bird above is a second cycle Ring-billed Gull in winter plumage. As this gull is only one year removed from adult, its plumage closely resembles adult plumage. Note, however, black markings on the shoulder, tertials, and tail, and the absence of A-spots.
ring-billed gull

I am not sure about this bird. Due to the extensive black in the wing and the black mark on the right outermost tail feather, I would say second cycle. However, I would not expect a second cycle bird to have such well developed A-spots and mirrors on the primaries (mirrors are white spots near the end of a primary which do not extend to the tip of the feather--depending on feather location and the age and species of gull, a single feather can have an A-spot and a mirror, an A-spot or a mirror, or neither one).


Adult
ring-billed gull

Here is an adult Ring-billed Gull. The eye is pale. Look also for the well developed A-spots and lack of stray black feathers in normally gray or white areas. The bird in the background appears also to be an adult, but it has noticeably yellower legs and bill. The legs and bill of breeding birds are normally quite yellow. Legs and bills of non-breeding adult birds vary from dull greenish yellow to fairly bright yellow. Breeding birds have clean white heads (no streaking) and a red orbital ring around the eye.
ring-billed gull

An adult in flight. This individual has a mirror on P10 (outermost primary) but no A-spot there. P9 has a mirror and also a small A-spot. P5 through P8 have A-spots only.

© 2004 Ray Bruun