Western Gull

Larus occidentalis

Gulls pt 3

“Kicking in chairs and knocking down tables
In a restaurant in a West end town
Call the police there’s a mad man around
Running down underground
To a dive bar in a West end town

In a West end town a dead end world
The East end boys and Western Gulls” … Ok that isn’t really how the Pet Shop Boys song goes, but you know you have all heard it that way!

Western Gulls are probably even more tricky to ID than Glaucous-winged Gulls, because

they hybridize so much with Glaucous-winged Gulls, and their hybrids are one of the most common gulls seen in Washington State. That being said, Western Gulls don’t stray far from the ocean – so when you catch that rare gull or two in the parking lot of some desert town, you can be assured it isn’t a Western Gull. Their range extends along the coast up into British Columbia and down through Baja California- staying in those extremes only during non-breeding seasons.

Beyond the nearness to the ocean, ID starts to get tricky fast. These gulls are described as large with a white head and upperparts, a dark slate grey back, and pink legs. Their backs are slightly darker than the Glaucous-winged, but their legs and beak are the same. The legs make them different than other gulls though, like the Thayer’s gull’s slightly darker, more purplish-pink legs in some individuals. Mew gull’s legs are usually dull yellow, Ring-billed bright yellow. Variation is the greatest in California gulls, who range from gray-green to bluish-green to yellow-green to yellow-orange in some individuals. And of course, our pink-legged Westerns also may have orange legs in breeding season.

If you are close enough or have a good camera or binocs, and can see their eyes – this can

help a little, since Western gulls and Thayer’s typically vary from brownish to yellowish Iris colors, although brown eye color is supposed to be diagnostic Thayer’s. Some Glaucous-winged have yellowish eyes, perhaps because of Western or even Herring genetic influence. Herring X Glaucous-winged hybrids may look like Herring but with brownish eyes. The variation in eye color in the large pink-legged gulls may all be attributable to hybridization. These descriptors are also filled with variations as the birds mature, go into breeding season, and during the winter! So I stuck with adults during non-breeding season for now.

Like most gulls, the Western Gull is an opportunistic feeder, capturing its own live prey, scavenging refuse, or stealing food from seals and other gulls. It is known to steal milk from lactating female seals while they lie on their backs sleeping on the beach!

Did you know? In colonies with many more females than males present, two females may establish a pair bond. Each lays eggs, and then takes care of the double-sized brood. The female-biased sex ratio of some Western Gull colonies may have been the result of pollution by pesticides that acted like estrogen and made some male embryos develop as females.