In the breeding season, the male Chestnut-collared Longspur is easily identified. The female and winter plumages are very similar to other longspurs. Smith's and Lapland have less white in the tail, especially at the base. McCown's has a rusty shoulder and a larger bill. Chestnut-collared often has a blackish breast and hint of chestnut on the nape which are lacking in the Smith's. Lapland Longspur has rusty wings. Chestnut-collared Longspur can be told from Snow Buntings and Horned Larks by its streaked upperparts and buff underparts.
Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.