NOUN: Either of two woodpeckers (Picoides arcticus or P. tridactylus) of northern North America, lacking the inner hind toe on each foot.
Length: 7.5 inches
Medium-sized black and white woodpecker
Narrow postocular stripe widens towards rear of head and extends down neck
White moustachial stripe
White throat, breast, and belly
White flanks with black barring
White back barred with black (in most races)
Black wings marked with white spots on flight feathers
Black tail with white outer tail feathers that are barred inwardly with black
Rocky Mountain subspecies (P. t. dorsalis) has an entirely white back
Eastern subspecies (P. t. bacatus) has a dark, heavily barred back
Western subspecies (P. t. fasciatus) has a whitish, sparsely barred back
Since Hairy Woodpeckers can have barred backs in the Maritimes provinces and Rocky Mountain Three-toed Woodpeckers have entirely white backs, it is best to concentrate on the barred flanks, much darker face, and narrow postocular stripe of the Three-toed Woodpecker there. Black-backed Woodpecker is distinguished from the Three-toed Woodpecker by the entirely black back, postocular stripe which does not extend down neck, and wholly white outer tail feathers.
Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.