Source : Webster's Revised Unabridged Dictionary (1913)

Rotche \Rotche\, n. (Zo["o]l.)
   A very small arctic sea bird ({Mergulus alle}, or {Alle
   alle}) common on both coasts of the Atlantic in winter; --
   called also {little auk}, {dovekie}, {rotch}, {rotchie}, and
   {sea dove}.

Source : WordNet®

little auk
     n : small short-billed auk abundant in arctic regions [syn: {dovekie},
          {Plautus alle}]