Bonaparte's Gull

Larus philadelphia

Order CHARADRIIFORMES - Family LARIDAE - Subfamily Larinae

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1. Cool Facts
2. Description
3. Similar Species
4. Sound
5. Range
6. Habitat
7. Food
8. Behavior
9. Reproduction
10. Conservation Status
11. Other Names

A small, graceful gull with bright white patches in its wings, the Bonaparte's Gull winters near people, but breeds in the isolated taiga and boreal forest.

Cool Facts

• The Bonaparte's Gull is the only gull that regularly nests in trees.
• The English name of the Bonaparte's Gull honors Charles Lucien Bonaparte, who made important contributions to American ornithology while an active member of the Academy of Natural Sciences of Philadelphia during the 1820s. The scientific name philadelphia was given in 1815 by the describer of the species, George Ord of Philadelphia, presumably because he collected his specimen there.

• During the breeding season, the Bonaparte's Gull feeds mainly on insects, often catching them on the wing.

Description

• Size: 28-38 cm (11-15 in)
• Wingspan: 76-80 cm (30-31 in)
• Weight: 180-225 g (6.35-7.94 ounces)

• Small gull.
• White triangle in outer part of wing.
• Back pale gray.
• Underparts white.
• Head black during breeding.
• Dark spot behind eyes in winter.

• Bill black.
• Mouth lining orange-red.
• Eyes black.
• Legs orange-red.

Breeding (Alternate) Plumage: Black hood. Narrow white crescents nearly meet behind eyes, but not in front. Back gray. White outer wing feathers with black tips. Tail white. May have pinkish blush on chest.
Nonbreeding (Basic) Plumage: Head entirely white, with dark spot behind the eyes. Dark smudges on top of head and above eyes. Neck dirty gray. Back gray. Underparts white.

Sex Differences

Sexes look alike.

Immature

Juvenile with much brown on head, neck, and back, a dark bar across the wing, and a black tail tip. Immature similar to nonbreeding adult, but with brownish black bar across the base of the wing, much black in the outer wing, and a black band across the tip of the tail. In first breeding plumage the black head is partly mottled with white.

Similar Species

• Terns have even longer, thinner wings, and have forked tails.
• Black-headed Gull has a longer and heavier, red bill, and blackish under the outer wing feathers. In breeding plumage the Black-headed Gull actually has a brownish hood that does not reach the back of the nape.
• Little Gull is smaller, with short, round wings, an all whitish back and wings, and blackish on the underside of the wings. Immature has dark cap and bold blackish "M" on wings, not the more narrow and broken "M" shown by Bonaparte's.
• Immature Black-legged Kittiwake shows a bolder "M" across the back and has a black line across the nape of its neck.

Sound

Call a buzzy "keh-keh."

»listen to songs of this species

Range

Summer Range

Breeds across Alaska and central Canada to Quebec.

Winter Range

Winters along coasts from Washington to southern Mexico and New Brunswick to the Caribbean, and along the Great Lakes and large inland lakes and rivers.

Habitat

Breeds around lakes and marshes in boreal forest. Winters along lakes, rivers, marshes, bays, and beaches along coasts.

Food

Small fish and large invertebrates, including insects. Does not eat garbage or carrion.

Behavior

Foraging

Flies along and plucks food from surface of water, or plunges into water to pick food from water.

Reproduction

Nest Type

Open cup of twigs, small branches, and bark, lined with mosses and lichens. Placed in tree or bent-over rushes.

Egg Description

Buffy green, with dark spots and blotches.

Clutch Size

Usually 3 eggs. Range: 1-4.

Condition at Hatching

Semiprecocial with eyes open. Covered in down. Able to stand within a day, but usually remain quiet in nest for a week.

Conservation Status

Numbers have increased over last 100 years.

Other Names

Mouette de Bonaparte (French)
Gaviota de Bonaparte (Spanish)

Sources used to construct this page:

Burger, J., and M. Gochfeld. 2002. Bonaparte?s Gull (Larus philadelphia). In The Birds of North America, No. 634 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.