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Bonaparte's Gull | Chroicocephalus philadelphia
Kleine kokmeeuw | Gaviota de Bonaparte
Bonaparte's Gull is a small, buoyant North American gull that nests in trees in the boreal forest, which is rare among gulls. It winters along the coasts and large lakes of the United States and reaches the Caribbean only in small numbers, mainly in the north.
Voice
A nasal, grating cherr or cheeer, also in flocks; calls little outside the breeding season.
Recording: Stanislas Wroza — CC BY-NC-SA 4.0 · converted to mono · xeno-canto
Identification
28–34 cm, one of the smallest gulls in the region, with a fine black bill and pink to orange-red legs. Adults have a pale grey mantle and a white wedge on the leading edge of the outer primaries, with a narrow black trailing edge; from below the primaries are pale and translucent. In breeding plumage the head is black with a broken white eye-ring, in winter white with a dark ear spot. First-year birds have a dark band across the wing coverts, a black trailing edge to the wing and a narrow black tail band.
Confusion species
Black-headed Gull Chroicocephalus ridibundus is larger, with a red or orange bill and dark grey undersides to the primaries. Laughing Gull Leucophaeus atricilla and Franklin's Gull Leucophaeus pipixcan are larger and darker grey, without a white leading edge to the primaries. Sabine's Gull Xema sabini has a white triangle on the rear of the wing and a forked tail.
Habitat
Sheltered bays, harbours, lagoons, salt pans and river mouths; it feeds in flight by picking from the surface, often with terns.
Where the bird is most at home, classified by the vegetation types of the Caribbean.
Range and movements
Rare winter visitor to the Bahamas, Cuba and Puerto Rico, with scattered records from the Cayman Islands, Jamaica, Hispaniola, the Virgin Islands and a few islands of the Lesser Antilles. Most records come in hard North American winters. Beyond the region it breeds from Alaska to eastern Canada and winters along the coasts of the United States and the Great Lakes, south to Mexico.
How and when to look
Flocks of gulls and terns in harbours and bays in the north of the region are the most promising. In flight the white leading edge of the wing stands out, and the small, slender bird flies lightly, like a tern.
Conservation status
Not threatened globally. In the Caribbean a rare winter visitor with no established population.
Scientific name
Chroicocephalus philadelphia | (Ord, 1815)
Ord described the species in 1815 as Sterna Philadelphia; because it was later moved to another genus, the author and year stand in brackets. The genus Chroicocephalus was introduced in 1836 by Eyton. Chroicocephalus combines the Ancient Greek khrōikos 'coloured' with -kephalos '-headed'. philadelphia is a Latinised adjective meaning 'from Philadelphia', after the place where the type specimen was collected. The specimen the first description was based on came from near Philadelphia, Pennsylvania.