The Collaborative International Dictionary of English v.0.48:

Manx \Manx\, a.
   Of or pertaining to the Isle of Man, or its inhabitants; as,
   the Manx language.
   [1913 Webster]

   Manx shearwater .
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Manx shearwater \Manx shearwater\ prop. n. (Zool.),
   A small black-and-white oceanic bird (Puffinus puffinus, or
   Puffinus anglorum), common in the Eastern North Atlantic.
   Called also Manx petrel, Manx puffin. It is avariety of
   shearwater. It was formerly abundant in the Isle of Man.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Manx shearwater
    n 1: small black-and-white shearwater common in the northeastern
         Atlantic [syn: Manx shearwater, Puffinus puffinus]