Source : Webster's Revised Unabridged Dictionary (1913)

Blackcap \Black"cap`\ (-k[a^]p`), n.
   1. (Zo["o]l.)
      (a) A small European song bird ({Sylvia atricapilla}),
          with a black crown; the mock nightingale.
      (b) An American titmouse ({Parus atricapillus}); the
          chickadee.

Chickadee \Chick"a*dee`\, n. (Zo["o]l.)
   A small bird, the blackcap titmouse ({Parus atricapillus}),
   of North America; -- named from its note.

Source : WordNet®

Parus atricapillus
     n : Chickadee having a dark crown [syn: {black-capped chickadee},
          {blackcap}]