Bonaparte's gull breeds on ponds or muskeg in coastal and inland areas, nesting mainly in low lying spruce and ramaracks close to or over water but up to 600 m in Alaska. It feeds on small fish, krill, amphipods and insects with the proportions varying geographically and seasonally. It feeds mainly by surface-seizing and diving, usually in flocks exceeding 2,000 birds over the incoming tide. It arrives at breeding grounds in early May, laying within the month. It is a non-colonial species though nests may be clumped (del Hoyo et al. 1996).

This species is found in North America, breeding from western Alaska (USA) to British Columbia, and east to eastern Quebec (Canada). It winters further south to northern Mexico on the Pacific and Atlantic coast including the Carribean. It can also be found wintering inland from Lake Erie to the valley of the Mississippi (del Hoyo et al. 1996).