Because of its unique feeding strategy, the White-breasted Nuthatch is most likely to confused with other nuthatches. Red-breasted Nuthatch has a black eyeline and reddish underparts. Brown-headed and Pygmy Nuthatches have brown caps and a white patch on the nape. Red-breasted, Pygmy and Brown-headed Nuthatches are mostly found in pines while the White-breasted prefers deciduous trees.
Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.