Thayer's Gull is a big marine bird that hails from North America and belongs to the Larus genus of the Laridae family. The binomial name of the gull is Larus Thayeri and it breeds in the Canadian Arctic islands and winters chiefly on the Pacific coast, from the southern parts of Alaska to the Californian Gulf, though there are wintering birds, as well, on the upper Mississippi River and the Great Lakes. This seabird has occurred as a vagabond to Denmark, Japan, and other divisions of Western Europe.
An adult Thayer's Gull will have a maximum body length that ranges from 22 inches to 25 inches (56 cm to 64 cm), with a wingspan, ranging from 51 inches to 58 inches (130 cm to 148 cm) and a body mass between 1.1 lbs and 2.4 lbs (720 grams and 1500 grams). Male Thayer's Gull birds are usually bigger than the female ones, and among normal measurements, the wing chord ranges from 15.1 inches to 17.4 inches (38.4 cm to 44.2 cm), the bill is measured from 1.7 inches to 2.2 inches (4.4 cm to 5.5 cm) and the measurement of tarsus lies between 2.0 inches and to 2.7 inches (5.2 cm and 6.9 cm).
The Thayer's Gull is rather intermediate in its appearance and habit between the Iceland Gull and the American Herring Gull. The Thayer's Gull was once considered a sub-variety of the Herring Gull, but currently it is being considered by many as one of the races of the Iceland Gull. Moreover, sometimes considered nonspecific with both species, the mature Thayer's Gull in non-propagation plumage has a pale gray color mantle, with clear black colored wingtips, and a wide brown lining on its neck and head. The neck, head, belly, breast, and the under wings of this marine bird are mostly white, and it has pink color legs. There is a red mark on its lower mandible, and with the dark colored iris, in general.
During the summer season, the neck of the Thayer's Gull are white, with the bill becoming bright yellow with a bigger red mark on its lower mandible. During the winter season, the Thayer's Gull are mostly found in small numbers in the middle of mixed groups of big gulls, though it may meet in huge numbers in certain places. In summer, Thayer's Gull birds can be largely seen on the tundra of elevated Arctic islands.
Juvenile Thayer's Gull birds are brown in color, with black color bills and legs, which will fade to adult pink quickly. Juvenal Plumage is varied from generally pale grayish brown to profound smoky brown. The back is marked with light tan and the wingtips are darker than the back. The inmost wing feathers, known as tertials are mostly dark with light rims, with a dusky tail and a black color bill.
The Thayer's Gull mostly feeds on Fish, offal in harbors, carrion, sea invertebrates, and sometimes it also feeds on eggs and juvenile of other birds.
The Thayer's Gull constructs its nest lined with moss, grass, or lichens. The female Thayer's Gull bird is capable of laying a maximum of 4 eggs in a single clutch. The eggs mostly assume blue or green color. The voice of these Thayer's Gull birds consists of typically squealing and mewing notes.