This large gull is very similar to Iceland Gull, and some have suggested that the two are actually one species. Thayer’s Gulls have a rounded head and fairly small bill, giving this bird a “gentle” expression compared to other large gulls. At rest, the primaries extend well beyond the end of the tail. Alternate Adult: The eye is usually dark, although some birds show a pale iris. The bill is yellow with a red gonydeal spot. The orbital ring is reddish purple. In flight, the upper sides of the primaries show black outer webs and white inner webs, giving the impression of long black fingers extending into the wingtips. The underside of the wing appears almost entirely white, with a narrow margin of dusky-gray on the tips of the primaries. The mantle is medium gray. The legs are a deep pink color. Basic Adult: The head and neck exhibit extensive dark streaking and a dark smudgy area surrounding the eye. The bill is pale yellow-green, with a more yellow tip. Third Cycle: Similar to adult, but with more blackish-brown in the primaries, some brown retained on the wing coverts, and variable amounts of dark on the tail. The bill is yellowish with a dark subterminal band. Second Cycle: Similar to first cycle bird, but with gray on the mantle. Body plumage generally paler than first cycle. The color of the primaries varies from quite dark dusky-brown to pale brown, but still shows the two-tone effect of the dark outer webs and pale inner webs. The bill is pale yellowish with a dark tip. First cycle: Young birds show the same round head, thin bill, and long primary extension as adults. The overall color is gray brown, with crisp mottling that approaches checkering in some birds. The primaries, while brown, have the dark outer webs and pale inner webs reminiscent of the adult wing pattern. The bill is dark, with variable amounts of dull pinkish at the base of the lower mandible.

Length: 58 (cm) Wingspan: 140 (cm)

Habitat:

Nests on steep cliffs. In winter, found along ocean shores, larger lakes and rivers, garbage dumps, urban parks.

Behavior:

Generally less aggressive than larger gull species.

Feeding:

Feeds on small fish, taken from the ocean surface. Like most gulls, takes advantage of any available food source in winter, both natural and man-made.