Appearance

Appearance

A pale, medium-large gull, 20–25 in (50–64 cm) long with a 45–59 in (115–150 cm) wingspan. About Herring Gull size but more graceful, with a short, slim bill and rounded head. Adult wingtips range from pure white to gray-marked (Kumlien's) to blackish (Thayer's); young birds are pale brown to whitish with a dark bill.

Voice

A laughing call like a Herring Gull's, but higher-pitched.

Look-alikes

Glaucous GullLarus hyperboreus

Glaucous is larger, with a longer, heavier bill. Young Glaucous Gulls have a pink bill with a neat black tip, while young Iceland Gulls have a mostly dark bill.

Why they get mixed up · Both are pale "white-winged" gulls in winter.

American Herring GullLarus smithsonianus

Iceland Gulls are usually a bit smaller and slimmer, with a shorter, slimmer bill and a rounder head. Dark-winged Thayer's-type birds can be very hard to tell from Herring Gulls in the field.

Why they get mixed up · Thayer's-type birds have darker wingtips and mix with Herring Gulls.

Where it lives

Typical habitats

• Coastal bays and harbors
• Estuaries
• Great Lakes
• Landfills

Range

Breeds on sea cliffs in Arctic Canada and Greenland. Eastern birds (mostly the "Kumlien's" type) winter from Labrador to New England, around Iceland, in smaller numbers on the Great Lakes, and in northwestern Europe. Thayer's-type birds winter mainly along the Pacific Coast from southern Alaska to the Gulf of California, with some on the Great Lakes and upper Mississippi River.

Seasonal presence

A winter visitor to the U.S.; it does not breed in the Lower 48.

Behavior

Diet

Small fish, mollusks, crustaceans, carrion, and some berries and seeds. In winter it often feeds at landfills, docks, sewage outlets, and around fishing boats.

Activity

Feeds in flight by dipping to the water's surface or plunging just below it; also forages while swimming or walking.

Life cycle

Nest

Nests in colonies on sea-facing cliff ledges, often with Black-legged Kittiwakes. The nest is a bulky mound of grass, moss, and seaweed.

Clutch size

2–3 eggs

Time to maturity

Takes about four years to reach maturity.

Connected species

Close relatives

• Thayer's GullLarus glaucoides thayeri

  The darker western form; considered a separate species until 2017.

• Kumlien's GullLarus glaucoides kumlieni

  The usual form in the Northeast, with gray-marked wingtips.

Name and classification

About the name

Thayer's Gull was long treated as its own species, but in 2017 the American Ornithological Society merged it into the Iceland Gull as a subspecies. Kumlien's Gull sits between the white-winged nominate birds and the darker Thayer's birds.

Conservation

IUCN Red List

LCLeast Concern·Low risk of extinction

Status

Winter numbers in New England appear to have increased over the past century.