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]

The Collaborative International Dictionary of English v.0.48:

Kinglet \King"let\, n.
   1. A little king; a weak or insignificant king. --Carlyle.
      [1913 Webster]

   2. (Zool.) Any one of several species of small singing birds
      of the genus Regulus and family Sylviid[ae].
      [1913 Webster]

   Note: The golden-crowned kinglet (Regulus satrapa), and the
         rubycrowned kinglet (Regulus calendula), are the most
         common American species. The common English kinglet
         (Regulus cristatus) is also called golden-crested
         wren, moonie, and marigold finch. The kinglets are
         often popularly called wrens, both in America and
         England.