Thayer's Gull

Thayer's Gull

Larus thayeri

The Thayer's Gull breeds in the high Arctic of Canada and winters along the northern Pacific Coast. It has become a more common winter visitor to the Great Lakes and the East Coast, but it is unknown whether increasing reports are due to increasingly eastward movement of the species or to more birders being aware of this rare gull.

Interesting Information

Thayer's Gull appears like a pale Herring Gull or a dark Iceland Gull. It was once considered a subspecies of Herring Gull, but now is considered by many a race of Iceland Gull.

Description

Adult Description

Size: 52-60 cm (20-24 in)
Weight: 1000 g (35.3 ounces)
Medium to large gull.
Head and underparts white.
Back light gray.
Wingtips streaked black-and-white, mostly pale below.
Bill yellow with red spot near tip of lower mandible.
Head rather rounded.
Underside of wingtip dark gray to silver.
Eyes usually dark brown, may be yellowish.
Legs deep pink.

Breeding (Alternate) Plumage

Head, neck, and underparts pure white. Back and wings light gray. Purplish red ring of skin around eyes. Bill yellow with red spot.

Nonbreeding (Basic) Plumage

Head and sides of breast variably streaked with dusky, sometimes forming a dirty hood. Dusky area in front of eye.

Sex Differences

Sexes look alike, male slightly larger.

Immature

Juvenal Plumage: Variable from overall light grayish brown to deep smoky brown. Back marked with light brown. Wingtips darker than back. Innermost wing feathers (tertials) mostly dark with light edges. Tail dusky. Bill all black.

First Winter (Basic I) Plumage: Like juvenal plumage.

Second Winter (Basic II) Plumage: Body and head mostly whitish. Back with some gray; wings still mottled with brown. Wingtips and tail darker. Bill dark with pale base.

Photo taken from: The Sibley Field Guide by David Allen Sibley

Habitat

Breeds in coastal colonies on rocky precipices of steep cliffs from low to high Arctic, normally facing fjords or sounds, though occasionally up to several kilometers inland. Winters along shores of salt water and less often freshwater lakes and rivers.

Behavior

Picks food off surface of water, food typically swallowed while flying.

Food

Fish, carrion, offal in harbors, marine invertebrates, occasionally eggs and young of other birds.

Taxonomy

Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Class:	Aves
Order:	Charadriiformes
Family:	Laridae
Subfamily:	Larinae
Genus:	Larus
Species:	Larus thayeri

Similar Species

Iceland Gull very similar to paler Thayer's Gulls, and some individuals may not be distinguishable. Iceland Gull generally has paler wingtips, often nearly white. Juvenile Iceland Gull has more light marking in the inner wing feathers (tertials) and a paler tail.
Herring Gull very similar to darker Thayer's Gulls, but adult has yellow eyes and usually has extensive blackish under the wingtips.
California Gull is smaller, has yellowish green legs, and a black spot in front of the red spot on the bill.
Ring-billed Gull smaller, with yellow legs in adult and distinct black ring around bill and no red spot. Immature Ring-billed Gull with thinner black band on tail.
Hybrids between Western and Glaucous-winged gulls are marked like Thayer's Gull, but are larger, more robust, and have very thick bills with a pronounced angle on the bottom.

Bird Sound

Calls are loud, clear bugling.

Eggs look like this

Photo taken from: ARCTOS Collaborative Collection Management Solution

	Sources Used To Construct This Page
	Snell, R. R. 2002. Iceland Gull (Larus glaucoides) and Thayer?s Gull (Larus thayeri). In The Birds of North America, No. 699 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.

	All photos and videos © Rick Swartzentrover - Free for non-profit use.