Gavia stellata
Order Gaviiformes
Family Gaviidae
Adult in summer.— Head and neck lead-gray; back of the neck streaked with white; fore neck rich chestnut; upper parts speckled with white; breast and belly white.
Adult in winter and Immature.— Upper parts, wings, and tail blackish-brown, speckled with white; throat, fore neck, and rest of under parts white.
The Red-throated Loon is a common migrant along the sea-coast in September and October, and again in April, and a not uncommon winter visitant. It occasionally occurs on large inland waters, as at Springfield, Mass., and on the Hudson. The adult breeding plumage with the red throat is very rare. Its feeding habits resemble those of the [Common Loon]. The two species resemble each other so closely in winter that it is difficult to be sure of the smaller species unless there is something else to measure it by, or unless one gets near enough to see the white speckling on the back.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)