The Collaborative International Dictionary of English v.0.48:

Pewee \Pe"wee\, n. [So called from its note.]
   1. (Zool.) A common American tyrant flycatcher (Sayornis
      ph[oe]be, or Sayornis fuscus). Called also pewit, and
      ph[oe]be.
      [1913 Webster]

   2. The woodcock. [Local, U.S.]
      [1913 Webster]

   Wood pewee (Zool.), a bird (Contopus virens) similar to
      the pewee (See Pewee, 1), but of smaller size.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Sayornis phoebe
    n 1: small dun-colored North American flycatcher [syn: phoebe,
         phoebe bird, Sayornis phoebe]