Smaller than most gulls, Bonaparte’s Gull is most easily identified by its size (13 inches), thin black bill, and bright orange legs. In summer, this species has a black head, gray body, and light gray wings that, unlike those of the similarly-patterned Laughing Gull (Leucophaeus atricilla), have white leading edges and black tips. In winter, this species becomes white-headed except for a small black spot behind the eye. Male and female Bonaparte’s Gulls are similar to one another in all seasons. Bonaparte’s Gull breeds over a wide area of southern Alaska and Canada east to Quebec. However, despite its large breeding territory, this species nests only locally within its breeding range. In winter, Bonaparte’s Gulls migrate south to the southern Great Lakes and coastal areas of the U.S.south to central Mexico. In summer, Bonaparte’s Gulls breed along open edges of northern evergreen forests near water, being among the only gulls to nest in trees. In winter, this species may be found along large bodies of fresh or salt water, including on riverbanks, sandy beaches, and the open ocean. Bonaparte’s Gull eats small fish at all seasons, but this species also eats insects while further inland in summer. Due to the relative inaccessibility of this species’ breeding grounds, most birdwatchers only observe Bonaparte’s Gulls during winter, when they are relatively common along the coasts. At this time of year, this species is most easily observed plunging into the water to catch small fish. Bonaparte’s Gull is most active during the day.

Threat Status: Least concern

Larus_philadelphia breeds in western Canada and Alaska from July to October. Bonaparte's gulls migrate south to spend the winter on the Pacific coast from Vancouver Island to points southward. Some migrate southward as far as Panama. They sometimes occur as vagrants in in a number of European countries as well as Japan, Israel, and Morroco.

Biogeographic Regions: nearctic (Native ); palearctic (Native ); ethiopian (Native ); neotropical (Native ); atlantic ocean (Native ); pacific ocean (Native )

Larus philadelphia breeds in western Canada and Alaska from July to October. Bonaparte's gulls migrate south to spend the winter on the Pacific coast from Vancouver Island to points southward. Some migrate southward as far as Panama. They sometimes occur as vagrants in in a number of European countries as well as Japan, Israel, and Morroco.

Biogeographic Regions: nearctic (Native ); palearctic (Native ); ethiopian (Native ); neotropical (Native ); atlantic ocean (Native ); pacific ocean (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: BREEDING: western and central Alaska, central Yukon, northwestern and central Mackenzie, and northern Manitoba south to base of Alaska Peninsula, south-coastal and (rarely) southeastern Alaska, southern British Columbia, southwestern Alberta, central Saskatchewan, southern Manitoba, and central Ontario. Nonbreeders occur in summer south along coast to California and New England, and in interior to Great Lakes. NON-BREEDING: from Washington south along coast to northwestern Mexico (southern Baja California, Sinaloa); Great Lakes; southeastern Canada south along coast to Florida, west to southern Texas and central Mexico; Bermuda, Bahamas, and Greater Antilles; occasional in Hawaii (AOU 1983, NGS 1983, Sibley and Monroe 1990).

Bonaparte's gulls are slate-gray headed with a very small black bill and bright orange-red legs and feet. They have a white terminal band on tail feathers and secondaries. In young birds, the wing has a dark-bordered appearance, with flashy white wing tips. Adults reach 43 to 53 cm in body length. (Pough 1953)

Range mass: 200 to 250 g.

Range length: 43 to 53 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike

Bonaparte's gulls are slate-gray headed with a very small black bill and bright orange-red legs and feet. They have a white terminal band on tail feathers and secondaries. In young birds, the wing has a dark-bordered appearance, with flashy white wing tips. Adults reach 43 to 53 cm in body length. (Pough 1953)

Range mass: 200 to 250 g.

Range length: 43 to 53 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike

Length: 34 cm

Weight: 212 grams

Bonaparte's gulls are found in ocean bays, coastal waters, islands, and lakes.

Habitat Regions: temperate ; saltwater or marine ; freshwater

Aquatic Biomes: lakes and ponds; coastal

Other Habitat Features: estuarine

• Terrestrial
• Freshwater
• Marine

Bonaparte's gulls are found in ocean bays, coastal waters, islands, and lakes.

Habitat Regions: temperate ; saltwater or marine ; freshwater

Aquatic Biomes: lakes and ponds; coastal

Other Habitat Features: estuarine

Comments: NON-BREEDING: along seacoasts, bays and harbors, estuaries, mudflats, marshes, rivers, lakes, ponds, and flooded fields (AOU 1983). More pelagic than most gulls, often feeds offshore (Braune 1989). BREEDING: coniferous woodland near ponds and lakes. Often nests in trees in old bird's nest (AOU 1983).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Migrates most commonly through eastern North America from Mississippi Valley east to Appalachians (AOU 1983). In fall, uses 3 flyways: the Pacific, Mississippi, and Atlantic, with the majority (60%) following the Mississippi Flyway from the Great Lakes to the Gulf of Mexico, and the remainder of the population split between the two coasts (21% Atlantic, 19% Pacific) (Braune 1989). Main fall routes through Atlantic Flyway: Saguenay River-Upper Saint John River-St. Croix River-Quoddy region, southwestern Bay of Fundy; Lower Great Lakes-Mohawk River-Hudson River-Long Island, New York area; Lower Great Lakes-Delaware River-Delaware Bay/Chesapeake Bay (Braune 1989). By late July, flocks of breeding birds form on larger boreal lakes prior to fall migration (Johnson and Herter 1989). Fall migration tends to be more coastal than does spring migration.

Small fish, crustacea, snails and marine worms are staple foods of Larus_philadelphia along the coast. However, inland in summer they feed chiefly on insects they capture in the air, pick from croplands, or gather from the surface of lakes or ponds. (Miklos 1994).

Small fish, crustacea, snails and marine worms are staple foods of Larus philadelphia along the coast. However, inland in summer they feed chiefly on insects they capture in the air, pick from croplands, or gather from the surface of lakes or ponds. (Miklos 1994).

Comments: Feeds primarily on insects and fishes in lakes and bays; also eats crustaceans and marine worms and scavenges (Bent 1921). July-December diet off New Brunswick: fishes, euphausiids, insects, polychaetes, amphipods; opportunistic feeder (Braune 1987). Young are fed insects gleaned from water surface or from water plants (Johnson and Herter 1989). Feeds on insects and marine invertebrates frequently in areas where prey concentrated by currents, waterfalls, glaciers, and other natural features (see Johnson and Herter 1989).

Nonbreeding: often seen in loose flocks; often associates with terns when feeding or resting.

The vocalizations of Bonaparte's gulls can be described as a harsh high pitched see-whee and a low pitched kuk-kuk-kuk. They produce many conversational whistled notes when feeding.

Communication Channels: visual ; acoustic

The vocalizations of Bonaparte's gulls can be described as a harsh high pitched see-whee and a low pitched kuk-kuk-kuk. They produce many conversational whistled notes when feeding.

Communication Channels: visual ; acoustic

Bonaparte's gulls nest in loose colonies throughout most of Canada, from Manitoba to west-central Ontario and north to Alaska. They are the only gull species that nests almost exclusively in nests built in trees, rather than on the ground. They lay two to four eggs in nests built from twigs and moss in spruce or tamarack trees near water. The eggs are grayish to greenish brown, marked with dark brown and lilac and 4.8 by 3.3 cm on average.

Breeding interval: Bonaparte's gulls breed once yearly.

Breeding season: Bonaparte's gulls breed from July to October each year.

Range eggs per season: 2 to 4.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)

Bonaparte's gulls nest in loose colonies throughout most of Canada, from Manitoba to west-central Ontario and north to Alaska. They are the only gull species that nests almost exclusively in nests built in trees, rather than on the ground. They lay two to four eggs in nests built from twigs and moss in spruce or tamarack trees near water. The eggs are grayish to greenish brown, marked with dark brown and lilac and 4.8 by 3.3 cm on average.

Breeding interval: Bonaparte's gulls breed once yearly.

Breeding season: Bonaparte's gulls breed from July to October each year.

Range eggs per season: 2 to 4.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)

Breeding begins mid-June (Harrison 1978). Incubates 2-3, usually 3, eggs for 24 days (Terres 1980). Nestlings are semi-precocial and downy. Usually nests solitarily or in small groups (Terres 1980).

The global population of Bonaparte's gulls is estimated to be between 260,000 and 530,000. This number seems to be stable.

IUCN Red List of Threatened Species: least concern

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

The global population of Bonaparte's gulls is estimated to be between 260,000 and 530,000. This number seems to be stable.

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N4N,N5B : N4N: Apparently Secure - Nonbreeding, N5B: Secure - Breeding

United States

Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding

Rounded Global Status Rank: G5 - Secure

There are no adverse affects of Bonaparte's gulls on humans.

Bonaparte's gulls are beneficial to agriculture, destroying insect pests, grubs, and worms in the fields.

Positive Impacts: controls pest population

There are no adverse affects of Bonaparte's gulls on humans.

Bonaparte's gulls are beneficial to agriculture, destroying insect pests, grubs, and worms in the fields.

Positive Impacts: controls pest population

Comments: Formerly included in Larus but separated on the basis of genetic data (Pons et al., 2005) that indicate that the genus would be paraphyletic if the following species were included: C. philadelphia, C. cirrocephalus, and C. ridibundus (AOU, 2008).