dobber

from The Collaborative International Dictionary of English v.0.48

Dabchick \Dab"chick`\ (d[a^]b"ch[i^]k`), n. [For dabchick. See
   {Dap}, {Dip}, cf. {Dipchick}.] (Zool.)
   A small water bird ({Podilymbus podiceps}), allied to the
   grebes, remarkable for its quickness in diving; -- called
   also {dapchick}, {dobchick}, {dipchick}, {didapper},
   {dobber}, {devil-diver}, {hell-diver}, and {pied-billed
   grebe}.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Dobber \Dob"ber\, n.
   1. (Zool.) See {Dabchick}.
      [1913 Webster]

   2. A float to a fishing line. [Local, U. S.]
      [1913 Webster]