Thayer's Gull (thayeri)

(last update: January 22, 2013)

Coordinators:
Amar Ayyash (USA)
Mars Muusse (Netherlands)

Glaucous-winged x Herring "Cook-Inlet" Gull glaucescens x smithsonianus adult, December 30 2011, Tukwila, 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).