The Black-bellied Plover is quite similar to the American Golden-Plover but has black axillaries, white wing stripe, thicker bill, and white rump in all plumages and white undertail coverts in breeding plumage. In most plumages the Black-bellied is distinctly grayer without any gold coloration. Pacific Golden-Plover is very similar but has white flanks and undertail coverts in breeding plumage. In basic plumage, Pacific has yellower head, supercilium and neck. Rare European Golden-Plover has white flanks and undertail coverts in alternate plumage and a less distinct supercilium in basic plumage. In all plumages, European has shorter wingtips that barely reach the end of the tail.
Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.