Pluvialis squatarola
Order Charadriiformes
Family Charadriidae
Subfamily Pluvialinae
Adult in spring.— Hind head and back black, spotted and barred with white; tail white, barred with brownish-black; wings showing white in flight; sides of head and neck, throat and breast, and upper belly black, bordered by white on each side, the white border meeting over the forehead; feathers under the raised wings black.
Adult in late summer and fall. — Upper parts dark brown, speckled with white; under parts white, with an occasional black feather; tail and wings as in spring.
Immature.— Upper parts lighter and with a golden shade on each feather; under parts white.
The Black-bellied Plover is a rather common migrant along the coast in spring and fall, passing north in May, and returning from late July to November. The young birds which appear in August are called Beetle-heads by the gunners; as they are more numerous than the adults and far less wary, they are more often seen by students. Both old and young frequent the mud-flats and sand-bars left bare by the tide; here they feed either alone or in company with Ring-necks, Turnstones, and Peep [Least and Semipalmated Sandpipers]. They scatter when feeding like Ring-necks and stand about heading in different directions, or after a short run, pick something from the sand. So far as I know, they do not bob, though all our other plovers do.
The notes of the Black-belly are among the most musical uttered by shore-birds; the call most often heard, either from flying or standing birds, consists of three syllables, all legato, the first prolonged, the second a bit lower and short, the last higher than the first. They are not unlike the toor-a-wee of a bluebird, but are lower in pitch, more prolonged and mournful. When feeding with other birds, the Black-bellies may easily be distinguished by their greater size; the whitish tail and the white in the wing readily identify them in flight. It is quite possible for a sharp eye to note the black axillars, the long feathers close to the body under the raised wing, either just as the bird raises his wings to fly, or as he takes his strokes.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)