The Bonaparte's Gull is an undersized gull that belongs to the genus Chroicocephalus of the family Laridae. The scientific name of this marine bird is Chroicocephalus Philadelphia and it is largely seen in North America. A strangely elegant, dove-like gull variety, this seabird is one among the smallest marine birds in North America. The Bonaparte's Gull is an arresting bird, particularly during the breeding period when the mature bird has a consistently sooty-black cover, wrapping the crown and the face, with distinct white crescents about its eyes.
The Bonaparte's Gull has a smaller body, but is bigger than the Saunders's Gull and the Little Gull among all gull varieties. An adult gull is capable of attaining a body length that ranges from 11 inches to 15 inches (28 cm to 38 cm), with a wingspan, ranging from 30 inches to 33 inches (76 cm to 84 cm) and a body weight between 5.7 Oz and 9.5 Oz (162 grams and 270 grams).
The Bonaparte's Gull encompasses a black color hood and a small slender dark bill. The body of the Bonaparte's Gull is mostly white in color with light gray upper wings and back. The under wing of the gull is pale and the tips of its wings are dark in color. The Bonaparte's Gull has pink color legs and its head will turn into white during winter.
During the first summer, the look of Bonaparte's Gull is analogous to that during its first winter, but paler because of wear. About less than 5% of these birds get a dark cover during their first summer, and on those that perform, the hood is more unexciting than on the reproductive adults.
The Bonaparte’s Gull has paler slate-gray colored shoulders, and a different black stripe runs along the trailing edge of its wings. The tail and the underparts of the bird are white in color, except for the gray colored neck and the sides of its breast that join with the gray colored upper parts.
During the breeding period the breast of the Bonaparte's Gull may demonstrate a slight rosy-pink hint. This marine bird has a spike-like, black colored bill, which is more slender and longer in male birds than the female ones. Both male and female birds have orange-red to pinkish legs.
During the non-breeding period, the Bonaparte’s Gull looses the unique black hood. Instead, the Bonaparte's Gull's head is completely white, even though it frequently has dark marks on its top and opposite its eyes, in addition to a famous, dark, remote ear-spot at the back of its eyes.
Young Bonaparte’s Gull birds boast a grayish-brown color upperparts and head, habitually with a dark ear-spot and cap. The Bonaparte's Gull's head may be partially spotted white in the summer. The wings of young gulls are pale gray on their upperparts and include a famous brownish-black bar across their wing, a thin, dark stripe around their wing tip, and strongly distinct external primaries. There is a thin black band at the tip of their tail.
The Bonaparte’s Gull mostly feeds on insects, but it also forages for krill, small fish, crustaceans, and other petite invertebrates, generally gathering in huge flocks to feed.
The breeding period in Bonaparte’s Gull in Canada and Alaska is short, lasting for just some weeks between the later part of May and the early part of July. These birds are strange among the gulls and they are the only gull species to nest chiefly in trees, instead on the ground. Both the female and male birds will contribute to the building of the solid, cup-fashioned nest, which is generally made from twigs, small boughs and tree bark, and creased with mosses, grasses and lichens. The nest is generally situated up to 13.2 feet (4 meters) over the land in a conifer species, like spruce, even though nests have also been seen on bent-over reeds and rushes around 3.3 feet (1 meter) above the water.
The maximum lifespan of the Bonaparte’s Gull is 18 years.