Thayer's Gull (thayeri)
(last update: January 22, 2013)
Glaucous-winged x Herring "Cook-Inlet" Gull glaucescens x smithsonianus 2nd cycle (3CY), January 01 2012, Sayer's Park, WA. Picture: Amar Ayyash.
Visit: Amar's Blog.
A known hybrid combo: Cook-Inlet. This Glaucous-winged x Herrings is pretty common around Seattle. These individuals tend to show smaller bills than Olympics. Some similarity to Thayer's Gull, but HYBRID GLAUCOUS-WINGED GULL X AMERICAN HERRING GULL (w. N. America) averages larger and bulkier with a bigger bill. Plumage and bare-part combinations can match Thayer’s, so attention to size and structure important. Hybrids often have broader wings with shorter wing projection (more like Glaucous-winged), orbital ring may show some yellowish (like Herring), and bill in winter often has dark distal marks (uncommon on Thayer’s; critical study needed of wingtip patterns).
Best separated from Thayer’s by structure, especially bigger bill; plumage characters need study.