The Collaborative International Dictionary of English v.0.48:

Redpoll \Red"poll`\ (-p?l`), n. (Zool.)
   (a) Any one of several species of small northern finches of
       the genus Acanthis (formerly Aegiothus), native of
       Europe and America. The adults have the crown red or
       rosy. The male of the most common species (Acanthis
       linarius) has also the breast and rump rosy. Called also
       redpoll linnet. See Illust. under Linnet.
   (b) The common European linnet.
   (c) The American redpoll warbler (Dendroica palmarum).
       [1913 Webster]

WordNet (r) 3.0 (2006):

redpoll
    n 1: small siskin-like finch with a red crown [syn: redpoll,
         Carduelis hornemanni]
    2: small siskin-like finch with a red crown and a rosy breast
       and rump [syn: redpoll, Carduelis flammea]