The Collaborative International Dictionary of English v.0.48:

Sprigtail \Sprig"tail`\ (spr[i^]g"t[=a]l`), n. (Zool.)
   (a) The pintail duck; -- called also sprig, and
       spreet-tail. [Local, U.S.]
   (b) The sharp-tailed grouse. [Local, U.S.]
       [1913 Webster]

WordNet (r) 3.0 (2006):

sprigtail
    n 1: large grouse of prairies and open forests of western North
         America [syn: sharp-tailed grouse, sprigtail, sprig
         tail, Pedioecetes phasianellus]