Source : Webster's Revised Unabridged Dictionary (1913)

Bluebird \Blue"bird`\, n. (Zo["o]l.)
   A small song bird ({Sialia sialis}), very common in the
   United States, and, in the north, one of the earliest to
   arrive in spring. The male is blue, with the breast reddish.
   It is related to the European robin.

   {Pairy bluebird} (Zo["o]l.), a brilliant Indian or East
      Indian bird of the genus {Irena}, of several species.