Thayer's Gull

Utah Winter Gulls

by Dennis Shirley

     Thayer's Gull (similar species)

Breeding Adult - brown eyes; small rounded head
Photo by Jack Binch ©Jack Binch

1st Winter - pale gray-brown plumage, whitish inner primaries, solid gray
subterminal tail band, little or no black on underwing tips
by Richard Young ©Richard B. Young

Thayer's Gull

Similar Species

Herring Gull - adults have pale eyes, black under wing tips and appear larger overall, especially the bill and head. First-winter Herring Gulls have blackish wing tips above which are darker than rest of wing; the underside of wing tips usually has some black. Second-winter Herring Gulls have black wing tips and tail band. Second-winter Thayer's Gulls resemble pale, washed-out second-winter Herring Gulls with a gray-brown tail band and wing tips.

Iceland Gulls - can not always by separated from pale adult Thayer's, but are usually not as dark on wing tips, the mantle is often paler, eyes are possibly darker brown. Also First-year Iceland Gulls are not always distinguishable from pale first-winter Thayer's, but lack a solid tail band, although tail mottling may suggest a weak tail band and first-winter Thayer's Gulls have uniform whitish flight feathers that are paler than upper wing coverts.

Glaucous-winged Gulls - are usually larger, have larger, thicker bill and slightly lighter wing tips; however, Glaucous-winged intergrades have darker primaries like Thayer's. Immature Glaucous-winged Gulls are smudgier looking overall than Thayer's; at rest and the primaries the same as or slightly paler than the rest of wing, not slightly darker as in Thayer's Gulls.

Breeding Adult Herring - has a larger yellow bill with an more orange spot;
also has a pale yellow eye and angular head (see below)
Photo by Merrill Webb ©Merrill Webb

1st Winter Iceland - usually not as dark on wing tips, mantle often paler, eye color possibly
darker brown. (First-year Iceland sometimes not distinguishable from pale first-winter Thayer's).
Photo by Paul Higgins ©Paul Higgins

Breeding Adult Glaucous-winged - usually larger, with larger,
thicker bill and slightly lighter wing tips than Thayer's.
Photo by Jack Binch ©Jack Binch

1st Year Thayer's - Immature Glaucous-winged are smudgier
overall than Thayer's especially at rest.
by Richard Young ©Richard B. Young