The Collaborative International Dictionary of English v.0.48:

Sandpiper \Sand"pi`per\, n.
   1. (Zool.) Any one of numerous species of small limicoline
      game birds belonging to Tringa, Actodromas,
      Ereunetes, and various allied genera of the family
      Tringidae.
      [1913 Webster]

   Note: The most important North American species are the
         pectoral sandpiper (Tringa maculata), called also
         brownback, grass snipe, and jacksnipe; the
         red-backed, or black-breasted, sandpiper, or dunlin
         (Tringa alpina); the purple sandpiper (Tringa
         maritima: the red-breasted sandpiper, or knot (Tringa
         canutus); the semipalmated sandpiper (Ereunetes
         pusillus); the spotted sandpiper, or teeter-tail
         (Actitis macularia); the buff-breasted sandpiper
         (Tryngites subruficollis), and the Bartramian
         sandpiper, or upland plover. See under Upland. Among
         the European species are the dunlin, the knot, the
         ruff, the sanderling, and the common sandpiper
         (Actitis hypoleucus syn. Tringoides hypoleucus),
         called also fiddler, peeper, pleeps, weet-weet,
         and summer snipe. Some of the small plovers and
         tattlers are also called sandpipers.
         [1913 Webster]

   2. (Zool.) A small lamprey eel; the pride.
      [1913 Webster]

   Curlew sandpiper. See under Curlew.

   Stilt sandpiper. See under Stilt.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dunlin \Dun"lin\, n. [Prob. of Celtic origin; cf. Gael. dun hill
   (E. dune), and linne pool, pond, lake, E. lin.] (Zool.)
   A species of sandpiper (Tringa alpina); -- called also
   churr, dorbie, grass bird, and red-backed sandpiper.
   It is found both in Europe and America.
   [1913 Webster]