The Collaborative International Dictionary of English v.0.48:

Yaffle \Yaf"fle\ (y[a^]f"f'l), n. [Probably imitative of its
   call or cry.] (Zool.)
   The European green woodpecker (Picus viridis syn. Genius
   viridis). It is noted for its loud laughlike note. Called
   also eccle, hewhole, highhoe, laughing bird,
   popinjay, rain bird, yaffil, yaffler, yaffingale,
   yappingale, yackel, and woodhack.
   [1913 Webster]