Ring-billed Gull (Larus delawarensis)
The Ring-billed Gull is a casual visitor to campus: one was seen with a flock of California Gulls on 03 Mar 2009 and 23 Jan 2010. It is a common migrant and wintering bird in southern California.
Adult Ring-billed Gulls in the winter have a light gray back, white head with grayish streaking on the back of the head and neck, white underparts, yellowish legs, a yellow bill with a black ring near the tip, and a pale eye. It takes four years for this species to attain adult plumage, and immature plumages vary by age. First winter birds (the most frequently encountered immature plumage) have heavily mottled brown upperparts, a mostly white head and underparts with some brown mottling, a dark eye, pink legs, and a pink bill with a black tip.