Junco \Jun"co\, n. (Zo["o]l.) Any bird of the genus Junco, which includes several species of North American finches; -- called also snowbird, or blue snowbird.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Snowbird \Snow"bird\, n. (Zo["o]l.)
   (a) An arctic finch (Plectrophenax, or Plectrophanes, nivalis) common, in winter, both in Europe and the United States, and often appearing in large flocks during snowstorms. It is partially white, but variously marked with chestnut and brown. Called also snow bunting, snowflake, snowfleck, and snowflight.
   (b) Any finch of the genus Junco which appears in flocks in winter time, especially J. hyemalis in the Eastern United States; -- called also blue snowbird. See Junco.
   (c) The fieldfare. [Prov. Eng.]

Source: Webster's Revised Unabridged Dictionary (1913)