Black-bellied Plover (winter plumage)
Pluvialis squatarola

f9 @ 1/1600s, ISO:800, Nikon D3S w 500mm and 1.7X tele-extender

"Black-bellied Plover," Wikipedia, the free encyclopedia. The grey plover, known as the black-bellied plover in North America, is a medium-sized plover breeding in Arctic regions. It is a long-distance migrant. They moult to winter plumage in mid August to early September and retain this until April; this being a fairly plain grey above, with a grey-speckled breast and white belly. The juvenile and first-winter plumages, held by young birds from fledging until about one year old, are similar to the adult winter plumage but with the back feathers blacker with creamy white edging. In all plumages, the inner flanks and axillary feathers at the base of the underwing are black, a feature which readily distinguishes it from the other three Pluvialis species in flightwide coastal distribution when not breeding.
Black Beach, West Falmouth, Massachusetts