- 20.5–23.6 in
- 35.3 oz
- Goéland de Thayer (French)
- Gaviota de Thayer (Spanish)
- 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.
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.
Fish, carrion, offal in harbors, marine invertebrates, occasionally eggs and young of other birds.
- Clutch Size
- 1–4 eggs
- Egg Description
- Variable grayish brown, spotted and blotched with dark brown.
- Condition at Hatching
- Alert and mobile. Covered in cryptically colored down.
Shallow bowl of moss and grass, placed on narrow cliff ledge.
Picks food off surface of water, food typically swallowed while flying.
There is little information of Thayer's Gull population trends. The North American Waterbird Conservation Plan estimates a breeding population in Canada of less than 10,000 birds. It rates the species a 14 out of 20 on the Contienntal Concern Score, and lists it as a Species of Moderate Concern. Thayer's Gull is not on the 2014 State of the Birds Watch List.
- 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.
- Kushlan, J.A., et al. 2002. Waterbird conservation for the Americas: the North American Waterbird Conservation Plan, version 1. Waterbird Conservation for the Americas. Washington, DC.
- North American Bird Conservation Initiative, U.S. Committee. 2014. State of the Birds 2014 Report. U.S. Department of Interior, Washington, DC.