The Collaborative International Dictionary of English v.0.48:

Buzzard \Buz"zard\ (b[u^]z"z[~e]rd), n.[O.E. busard, bosard, F.
   busard, fr. buse, L. buteo, a kind of falcon or hawk.]
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   1. (Zool.) A bird of prey of the Hawk family, belonging to
      the genus Buteo and related genera.
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   2. (Zool.) In the United States, a term used for the turkey
      vulture (Cathartes aura), and sometimes
      indiscriminately to any vulture.
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   Note: The Buteo vulgaris is the common buzzard of Europe.
         The American species (of which the most common are
         Buteo borealis, Buteo Pennsylvanicus, and Buteo
         lineatus) are usually called hen hawks. -- The
         rough-legged buzzard, or bee hawk, of Europe (Pernis
         apivorus) feeds on bees and their larv[ae], with other
         insects, and reptiles. -- The moor buzzard of Europe is
         Circus [ae]ruginosus. See Turkey buzzard, and
         Carrion buzzard.
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   Bald buzzard, the fishhawk or osprey. See Fishhawk.
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   2. A blockhead; a dunce.
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            It is common, to a proverb, to call one who can not
            be taught, or who continues obstinately ignorant, a
            buzzard.                              --Goldsmith.
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