glaucoides - kumlieni
(last update: January 26, 2012)
Western Gull X Glaucous-winged Gull hybrid ("Olympic Gull"). Pictures: John Rakestraw.
Western Gull X Glaucous-winged Gull hybrid (Olympic Gull): an even blending of characteristics of both parent species. The mantle is darker than a pure GW, but Westerns never show this much mottling on the head and neck. The wingtips are dark, but not actually black. You can tell this is a third cycle individual by the tiny bit of black on the tail and by the odd pattern on the bill. These hybrids show a great deal of variation, and are often the most numerous gulls in the area.
These two taxa and their hybrids all interbreed extensively in western North America and the resultant offspring can show almost any combination of parental characters (Bell 1996, 1997; Howell, pers. obs.). While the wingtip pattern of this intergrade combination can resemble Thayer’s Gull closely (e.g. Howell and Elliott 2001), the extent of dark in the wingtips is typically more extensive than shown by Kumlien’s Gull. These hybrids are also darker grey above than Kumlien’s Gull, as well as being larger and bulkier with notably stouter bills (with a more swollen gonys). Other features to separate this hybrid combination from Kumlien’s Gull include orbital ring colour (often including some yellowish; a Western Gull trait), and bill colour (often flesh-coloured basally with a dark subtetminal band, a Glaucous-winged trait).
