Source : Webster's Revised Unabridged Dictionary (1913)

Yellowlegs \Yel"low*legs`\, n. (Zo["o]l.)
   Any one of several species of long-legged sandpipers of the
   genus {Totanus}, in which the legs are bright yellow; --
   called also {stone snipe}, {tattler}, {telltale},
   {yellowshanks}; and {yellowshins}. See {Tattler}, 2.

Source : WordNet®

yellowlegs
     n : either of two North American shorebird with yellow legs