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.
Common migrant, March to May and September to December; occasionally winters in large numbers along rivers and bays. Adults have a dark sooty slate head and throat in the spring, washed with grayish colors in the autumn. Immature birds may be identified by the black band on the tail. Sexes are alike.
The bird shown at the top is an adult female in breeding plumage; this bird is on the left in the exhibit.
Collected By: R Ridgway
Locality: Potomac River, near Washington DC
Catalog ID: 84772
The bird in the lower panel is young female in winter plumage (the head is white); this bird is on the right in the exhibit.
Collected By: C Drexler
Locality: Washington, DC
Catalog ID: 12691