All species › Waders, gulls and terns › Skimmers, noddies, terns and gulls › Bonaparte's Gull
Bonaparte's Gull | Chroicocephalus philadelphia
Kleine kokmeeuw | Gaviota de Bonaparte | Gaivota-de-bonaparte
Bonaparte's Gull is a small, light-flying gull of the boreal forests of North America that winters along the coasts of the United States and Mexico. Farther south it is rarely seen. In the guide area it has been recorded only as a very rare vagrant.
Voice
A dry, grating krrr or gerr, somewhat tern-like.
Recording: Stanislas Wroza — CC BY-NC-SA 4.0 · xeno-canto
Identification
31–34 cm, a small gull with a thin black bill and pink legs. Adults have a pale grey mantle and a white leading edge to the outer wing with a narrow black trailing edge to the wingtip; the underwing is pale. In breeding plumage a blackish grey hood; in non-breeding plumage a white head with a dark ear spot. Juveniles and first-winter birds have a dark band across the upperwing and a black tail band. The sexes are alike.
Confusion species
Black-headed Gull Chroicocephalus ridibundus is larger, with a red or reddish bill and dark undersides to the primaries. Grey-headed Gull Chroicocephalus cirrocephalus is larger, with a pale iris, a red bill and much black in the wingtip. Sabine's Gull Xema sabini has a black outer wing with a white triangle and a forked tail.
Habitat
Estuaries, lagoons, harbours and inshore waters; in North America also large lakes. It takes small fish and invertebrates from the water surface in flight or while swimming. It does not breed in the guide area.
Where the bird is most at home, classified by the vegetation units of the Andes and the west coast.
Range and movements
Only a very rare vagrant on the coast of the guide area; the first record for Ecuador and South America dates from November 2013. Breeds in the boreal forests of Alaska and Canada and winters along the coasts of the United States, Mexico and the Caribbean.
How and when to look
A vagrant is most likely among flocks of Franklin's and Laughing Gulls and terns at estuaries and harbours on the coast in the northern winter; look for the small size, the thin black bill and the white leading edge to the outer wing.
Conservation status
Least Concern. The world population is large and fairly stable.
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. The genus name is from Greek khrōikos, 'coloured', and -kephalos, '-headed', after the coloured head in breeding plumage. The species name refers to Philadelphia, Pennsylvania, where the type came from. The specimen the first description was based on came from Philadelphia, Pennsylvania, United States.