glaucoides - kumlieni
(last update: January 26, 2012)
Possible Herring Gull X Glaucous-winged Gull October 30 2008, Parksville Community Park, Vancouver island, BC. Picture: Guy Monty.
These two taxa hybridise extensively in northwestern North America and the resultant offspring can apparently show any combination of parental characters (Patten 1980; Howell, pers. obs.). The plumage of this hybrid combination can quite closely resemble that of Kumlien’s Gulls with extensively dark-marked primaries. But the extent of dark in the wingtips is typically more extensive than shown by Kumlien’s Gull, and these hybrids should be slightly darker grey above than Kumlien’s Gull. In addition, hybrids differ from Kumlien’s in their larger size and bigger and heavier bills (but some appear very similar to Thayer’s). Most adults of this hybrid combination are identifiable in the field, given observer experience and the presence of other gulls for comparison. Their larger and longer bills, larger overall size and bulkier structure should preclude confusion with the smaller and shorter-billed Kumlien`s Gull, but some duplicate Thayer’s so closely that they can be passed off as that taxon (Howell and Corben 2000, Howell and Elliott 2001).
