The Collaborative International Dictionary of English v.0.48:

Goldcrest \Gold"crest`\ (g[=o]ld"kr[e^]st`), n. (Zool.)
   The European golden-crested kinglet (Regulus cristatus, or
   Regulus regulus); -- called also golden-crested wren, and
   golden wren. The name is also sometimes applied to the
   American golden-crested kinglet. See Kinglet.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Regulus regulus
    n 1: European kinglet with a black-bordered yellow crown patch
         [syn: goldcrest, golden-crested kinglet, Regulus
         regulus]