The Collaborative International Dictionary of English v.0.48:

Snakebird \Snake"bird`\, n. [So named from its snakelike neck.]
   (Zool.)
   1. Any one of four species of aquatic birds of the genus
      Anhinga or Plotus. They are allied to the gannets and
      cormorants, but have very long, slender, flexible necks,
      and sharp bills.
      [1913 Webster]

   Note: The American species (Anhinga anhinga syn. Plotus
         anhinga) inhabits the Southern United States and
         tropical America; -- called also darter, and water
         turkey. The Asiatic species (Anhinga melanogaster)
         is native of Southern Asia and the East Indies. Two
         other species inhabit Africa and Australia
         respectively.
         [1913 Webster]

   2. (Zool.) The wryneck.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wryneck \Wry"neck\, n. (Med.)
   [1913 Webster]
   1. A twisted or distorted neck; a deformity in which the neck
      is drawn to one side by a rigid contraction of one of the
      muscles of the neck; torticollis.
      [1913 Webster]

   2. a person suffering from torticollis.
      [PJC]

   3. (Zool.) Any one of several species of Old World birds of
      the genus Jynx or subfamily Jynginae, allied to the
      woodpeckers; especially, the common European species
      (Jynx torguilla); -- so called from its habit of turning
      the neck around in different directions. Called also
      cuckoo's mate, snakebird, summer bird, tonguebird,
      and writheneck.
      [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

snakebird
    n 1: fish-eating bird of warm inland waters having a long
         flexible neck and slender sharp-pointed bill [syn:
         snakebird, anhinga, darter]