Bird of the Month - December 2005
California Gull
Larus californicus
To those people who experience gulls only as ornaments along the shore or in the sky, little or no distinction might be made between the many species. But it might be muttered by birders who have stumbled across one too many hybrid gulls that the birds themselves make little distinction! For the person who is beginning to look at gulls in something other than an esthetic sense, there is hope in making these distinctions, for most gulls don’t hybridize, and most exhibit characteristics that allow them to be identified with reasonable assurance. The California Gull is among these “easy” gulls.
California Gulls breed on islands in lakes and wetlands in interior western Canada, the northern Great Plains and Great Basin, and locally elsewhere in the West, as in South San Francisco Bay. They are almost unknown on the Atlantic Coast. These are social birds throughout most of the year, even while nesting, although pairs of adults defend space within their crowded colonies sufficient to incubate the 2 or 3 brownish-olive eggs for 23-27 days.
After nesting, they move generally westward. During late summer and autumn, they may be numerous at mountain lakes. Juveniles are quite precocious, reaching the ocean beaches and waterfronts of the Redwood Region two weeks earlier than the locally produced young Western Gulls. A noticeable southward migration takes place along the coast in October and November, at which time flocks consisting largely of this species can be seen flying over the breakers and the outer beach. Many California Gulls spend part of the nonbreeding season far offshore over the open ocean. In late March and April, a return flight of sharp-looking breeding adults moves northward along the coast and inland, followed by one-, two-, and three-year-old birds too young to attempt to breed. A few such youngsters may show up or linger coastally during May, June, and July.
California Gulls are known for appearing in large flocks at crop fields, in wet pastures, and on lawns and athletic fields. This behavior is much more obvious inland than along our coast, where most Cals resort to the open beaches and river mouths. During the summer, insects constitute much of their diet. This is the gull made famous by rescuing Mormon settlers in Utah from a plague of locusts in 1848.
These birds require more than three years to reach adulthood, and each molt causes a maturing gull to assume a different appearance. Adults have yellow or greenish bills; unlike other gulls, the lower mandible is marked with both a red and a black spot. Gull identification, though rewarding, is an endless challenge. Field guides will indicate how varied gulls are and will show how to distinguish species and age-specific plumages.