Slaty-backed Gull

Larus schistisagus

Order

CHARADRIIFORMES

Family

Gulls, Terns, Skimmers (Laridae)

Code 4

SBGU

Code 6

LARSCH

ITIS

Egg Color:

Brown or olive buff with brown or black spots.



Number of Eggs:

2 - 3



Incubation Days:

26 - 28



Egg Incubator:

Unknown



Nest Location:

Seacliffs, rocky islands, occasionally sandy beaches.



Nest Material:

Seaweed



Migration:

Migratory



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General

Slaty-backed Gull: Large gull with dark slate-gray back and upper wings; darker outer primaries are separated from mantle by staggered row of white spots. Undersides of primaries are gray; broad white trailing edge to wings. Legs and feet are bright pink and eyes are yellow with red orbital ring; bill is yellow with red spot near tip. Sexes are similar. Winter adult shows brown streaking on head and neck and dark streak through eye. Juvenile is dull gray-brown with white lower belly and black bill.

Range and Habitat

Slaty-backed Gull: Breeds in northeastern Eurasia. Winters from the Bering Sea and Kamchatka south to Japan and the coast of eastern China. Regularly wanders to the Aleutian Islands and coast of western Alaska; there is at least one inland record for the United States. Breeds on cliffs and rocky islands.

Breeding and Nesting

Slaty-backed Gull: Colonial; seaweed nest on seacliffs, rocky, islands, or occasionally sandy beaches. Two to three brown or olive buff eggs spotted with brown or black. Incubation ranges from 26 to 28 days and is carried out by both sexes; first flight at 49 to 56 days.

Foraging and Feeding

Slaty-backed Gull: These gulls are scavengers and omnivores. They forage on mudflats. Their diet varies, but consists mainly of fish and invertebrates such as crabs and sea urchins, but also carrion, refuse, offal, bird eggs and chicks, voles and insects. They also take fish and roe during salmon spawning, leftovers from bear-kills, berries and waste from fisheries and slaughterhouses.

Vocalization

Slaty-backed Gull: Deep, gutteral "kaaw," or "klaaw."

Similar Species

Slaty-backed Gull: Winter Western Gull has thicker bill, more extensive black on primary tips, absence of streaking on head and neck.

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BellyX
The ventral part of the bird, or the area between the flanks on each side and the crissum and breast. Flight muscles are located between the belly and the breast.
MantleX
The upper surface of the back and wings covered with shorter feathers.
Outer primariesX
The outer primaries are the primary feathers on the wing farthest from the body. They often appear to be the longest feathers on the wing.
PrimariesX
The primaries are the flight feathers specialized for flight. They are attached to the "hand" equivalent part of the wing.
Parts of a Standing bird X
Head Feathers and Markings X
Parts of a Flying bird X