The Collaborative International Dictionary of English v.0.48:

Blackbird \Black"bird\, n.
   1. Among slavers and pirates, a negro or Polynesian. [Cant,
      pejorative]
      [Webster 1913 Suppl.]

   2. A native of any of the islands near Queensland; -- called
      also Kanaka. [Australia, pejorative]
      [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Blackbird \Black"bird\ (bl[a^]k"b[~e]rd), v. i.
   to engage in the slave trade. [Colloq.]
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Blackbird \Black"bird\ (bl[a^]k"b[~e]rd), n. (Zool.)
   In England, a species of thrush (Turdus merula), a singing
   bird with a fin note; the merle. In America the name is given
   to several birds, as the Quiscalus versicolor, or crow
   blackbird; the Agel[ae]us ph[oe]niceus, or red-winged
   blackbird; the cowbird; the rusty grackle, etc. See
   Redwing.
   [1913 Webster]

WordNet (r) 3.0 (2006):

blackbird
    n 1: any bird of the family Icteridae whose male is black or
         predominantly black [syn: New World blackbird,
         blackbird]
    2: common black European thrush [syn: blackbird, merl,
       merle, ouzel, ousel, European blackbird, Turdus
       merula]