What is a Bonaparte’s gull?

Quick Facts

Bonaparte’s gull is a small gull species that breeds in North America and winters along the coasts of North America. Here are some quick facts about Bonaparte’s gulls:

• Scientific name: Chroicocephalus philadelphia
• Average length: 13-15 inches
• Average wingspan: 32-37 inches
• Average weight: 5-7 ounces
• Lifespan: Up to 17 years
• Conservation status: Least Concern

Identification

Bonaparte’s gull is a petite, slender gull with a black hood and white undersides during breeding season. Here are some tips for identifying Bonaparte’s gull:

• Black hood becomes scruffy and mottled in winter
• Reddish-orange legs
• Reddish bill with black tip
• Pale grey upperparts
• White wedge-shaped tail
• Juveniles have black bill and legs

Bonaparte’s gull is often confused with other small gull species like the little gull and black-headed gull. The key differences are:

Range and Habitat

Bonaparte’s gulls have a large breeding and wintering range across North America:

• Breed in boreal forests and wetlands of Alaska, Canada, and the northern U.S.
• Winter along the Pacific, Gulf, and Atlantic Coasts south to Mexico
• Also found inland on lakes, rivers, and agricultural fields in winter

During migration, Bonaparte’s gulls can be found across much of the U.S. and southern Canada. They frequent inland wetlands, lakes, rivers, and agricultural fields.

Breeding Habitat

Bonaparte’s gulls nest in isolated colonies in wetlands and forests across Canada and Alaska:

• Nest in trees near lakes, ponds, and slow-moving streams
• Also nest on the ground on islands and wetlands
• Prefer habitats with plenty of small fish and insect food sources

Winter Habitat

In winter, Bonaparte’s gulls inhabit coastal areas and inland wetlands:

• Coastlines, marshes, estuaries, harbors
• Lakes, rivers, flooded fields
• Roost on beaches, mudflats, wet fields, and ice shelves

They usually winter in groups, sometimes in the thousands, and will gather to roost at night.

Diet

Bonaparte’s gulls are opportunistic feeders that prey on small fish, insects, crustaceans, and other invertebrates. Their diet includes:

• Small fish – minnows, sticklebacks, killifish, smelt
• Aquatic insects – dragonflies, mayflies, caddisflies
• Crustaceans – shrimp, crabs, crayfish
• Worms, mollusks, plankton

They forage by dipping and surface plunging in shallow waters. They also pick prey items while walking along shorelines. In agricultural areas, they will follow plows to pick up disturbed insects.

Breeding and Nesting

Bonaparte’s gulls build nests and breed in colonies in May-July:

• Lay 2-4 eggs in nests built on the ground or in trees
• Nests are made of twigs, grasses, mosses
• Both parents incubate eggs for around 23 days
• Young fledge at 4-5 weeks old

Nesting colonies are often located near prime feeding habitats like shallow ponds, marshes, and streams. Nesting territories are aggressively defended from predators and other gulls.

Courtship

In spring, Bonaparte’s gulls arrive at breeding sites and engage in courtship displays:

• Aerial displays – soaring, diving, calling
• Head tossing and bowing on the ground
• Mates chosen for the breeding season
• Pairs stay together for nest building and breeding

Chicks

Bonaparte’s gull chicks are semi-precocial at hatching:

• Covered in downy feathers
• Leave nest within 1-2 days
• Fed by parents for 4-5 weeks until fledging
• Parents fiercely defend chicks from predators
• Mortality can be high from weather, predators, starvation

Migration

Bonaparte’s gulls migrate long distances between breeding and wintering areas:

• Spring migration to breeding grounds in April-May
• Fall migration from August-October
• Travel distances up to 2,400 miles between seasons

Their migration includes long flights over land and stopovers at inland wetlands:

Conservation Status

Bonaparte’s gull has a large population and range. Their status is of Least Concern:

• Global population estimated at over 300,000 birds
• Population trend appears to be increasing
• Adaptable and opportunistic feeders

Potential threats include:

• Habitat loss in breeding areas
• Disturbance of nesting colonies
• Pollution and contamination

However, Bonaparte’s gulls remain widespread and abundant across their habitat range. Their ability to thrive around humans improves their long-term outlook.

Interesting Facts

Here are some interesting facts about the Bonaparte’s gull:

• Named after Charles Lucien Bonaparte, a leading French ornithologist in the 1800s
• One of the most petite gulls in North America
• The only small gull with a black hood in breeding plumage
• Will migrate incredible distances, up to 2,400 miles
• Agile fliers that capture insects in mid-air
• Young chicks will leave the nest after only 1-2 days
• Often found in large flocks of thousands of birds in winter

Where to See Bonaparte’s Gulls

Here are some top places to spot Bonaparte’s gulls throughout their range:

Breeding Areas

• Wood Buffalo National Park, Alberta
• Kenai National Wildlife Refuge, Alaska
• Selawik National Wildlife Refuge, Alaska
• Lake Ontario, Ontario
• Lake Winnipeg, Manitoba

Migration Stopovers

• Lakes and reservoirs of the Great Plains
• Prairie Pothole wetlands
• Columbia River, Pacific Northwest
• Great Salt Lake, Utah
• Lake Champlain, Vermont

Wintering Sites

• Salton Sea, California
• Texas Gulf Coast
• Florida Gulf Coast and Keys
• Coasts of the Mid-Atlantic and Northeast

Check shallow lakes, marshes, harbors, and shorelines for wintering and migrant Bonaparte’s gulls.

Conclusion

In summary, the Bonaparte’s gull is a small and striking gull species known for its black hood and long seasonal migrations across North America. It breeds in northern forests and winters along ocean coasts and inland lakes and rivers. Bonaparte’s gulls are opportunistic feeders that thrive around humans. With a large population and range, the Bonaparte’s gull remains a summer sight at breeding sites and a common winter visitor across much of the continent. Their adaptability ensures that Bonaparte’s gulls will continue to migrate and flourish across North America for years to come.