Choicocephalus philadelphia
Order Charadriiformes
Family Laridae
Subfamily Larinae
Adult in spring and summer.— Head black; tail and under parts white; back and wings pearl-gray; outer wing-feathers white nearly to the tip, which is black; bill black; feet rich orange-red.
Adult in autumn.— Head whitish, a dusky spot back of the eye; otherwise like the adult in summer; bill black; feet pale flesh-color.
Immature.— Similar to fall adult, but tail crossed at the tip by a black band.
Bonaparte’s Gull is a common migrant along the coast of New York and New England, a rare migrant on the Hudson, and a rather rare straggler to other inland waters, occurring in April and from August to October; it winters sparingly from Maine southward. It is an unsuspicious species, allowing a near approach. In grace it almost equals the terns, sinking gently on the water or feeding daintily just over the surf. In spring it is easily distinguished from all other gulls, except the Laughing Gull, by the black head and throat. In fall, when it has lost this plumage, it may be distinguished from the Herring Gull by its size, from the Kittiwake by its black bill and by its preference for the inshore waters, and from the Laughing Gull at this season by the wings, which have the general effect of white, tipped with black. The young birds have the tip of the tail crossed by a broad black band. Along the coast of Maine and north of Cape Cod the Laughing Gull is very rare; south of Cape Cod in the summer the Bonaparte’s Gull does not occur.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)