I am interrupting my march down memory lane to bring you a photo of two Western Gulls (Goéland d’Audubon / Larus occidentalis). This photo is also an excuse to talk about our confusing West Coast gulls. Birders in this part of the world are keenly aware that one of the most common birds on our coast, gulls, are notoriously difficult to ID. This is the case because the birds on the Canadian and American Pacific coast, from Alaska to California, like to interbreed and when the do, the resulting hybrids are difficult (if not impossible) to tell apart from the “purebred” species. The four species that most commonly guilty of this inter-species fooling around are the Glaucous, Glaucous-winged, Herring and Western Gulls. In fact, in the case of Glaucous-winged and Western Gulls, Sibley indicates (on p. 222 of the 2nd edition of his Guide to Birds) that most gulls of either species seen in Washington State seem to be hybrids.
Getting back to the photo above, I am very happy to report that once I could take a look at my photos, I was able to determine that these are clearly Western Gulls: The wintering adult’s wings are significantly darker than a Glaucous-winged’s (and the darker primaries give it a two-toned look), not to mention that the head is almost completely white (in winter, a GWGU’s head is smudged in brown). But the clincher is the 1st winter bird, which is darker brown than its cousin, also has a pale base at the lower mandible. I was very glad to be able to get several good photos of this species, which is far less common than the GWGU in this part of British Columbia.