The Collaborative International Dictionary of English v.0.48:

Shadbird \Shad"bird`\ (sh[a^]d"b[~e]rd), n. (Zool.)
   (a) The American, or Wilson's, snipe. See under Snipe. So
       called because it appears at the same time as the shad.
   (b) The common European sandpiper. [Prov. Eng.]
       [1913 Webster]