Western Gull

Larus occidentalis
Range Map

The aptly named Western Gull is strictly a resident of the west coast of the USA, north to southern British Columbia and south to the northern Pacific coast of Baja California. In the northern end of its range, these birds frequently interbreed with Glaucous-Winged Gulls.

These large west coast gulls are among the most prominent gull species we see along the USA’ Pacific coast. However, because their range is restricted to the narrowest bands along the coastline, their population is smaller than most North American gulls. Estimates of their population are about 40,000 pairs, with only about 200 nesting sites total. Most of their nesting takes place on islands off the Pacific coast, with 30% breeding on Southeast Farallon Island.

The Yellow-footed Gull (Larus livens) of the Sea of Cortez in the Gulf of California (Mexico) was formerly considered a subspecies of the Western Gull, but is now considered a separate species. There are but two subspecies of Western Gull recognised by today’s taxonomists:

  • L. o. occidentalis is considered the northern member of this family. They live from central California to Washington and are usually larger than their cousins.
  • L. o. wymani is the southern member of this clan. They live from Monterey Bay in central California south to Baja California and Guadalupe Island (Mexico).

It takes four years for Western Gulls to reach adulthood. As they age, they transform from gray-brown juveniles to their first-year, second-year and third-year plumages; all considerably different from their earlier garments, and nothing like their elegant adult feathering. I’m better at seeing their differences than I used to be, but aging gulls is not my strongest subject.


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