The Collaborative International Dictionary of English v.0.48:

Turnstone \Turn"stone`\, n. (Zool.)
   Any species of limicoline birds of the genera Strepsilas
   and Arenaria, allied to the plovers, especially the common
   American and European species (Strepsilas interpres). They
   are so called from their habit of turning up small stones in
   search of mollusks and other aquatic animals. Called also
   brant bird, sand runner, sea quail, sea lark,
   sparkback, and skirlcrake.
   [1913 Webster]

   Black turnstone, the California turnstone (Arenaria
      melanocephala). The adult in summer is mostly black,
      except some white streaks on the chest and forehead, and
      two white loral spots.
      [1913 Webster]