Individual variation in Furnarius leucopus torridus (Furnariidae, Aves). American Museum novitates ; no. 2515

Abstract

"The individuals of Furnarius leucopus torridus that have been collected in the upper Amazon Basin, from the upper Solimoes westward into Amazonian Peru, differ conspicuously in the saturation of their plumage, and to a lesser extent in other characters. Some specimens are very dark, others are much paler. The variation appears to be merely individual and was first discussed by Hellmayr (1925) who called attention to the existence of intermediate specimens, but Zimmer (1936), working with different and less representative material, came to the conclusion that two distinct species were involved. The present paper reinvestigates this question and supports the opinion of Hellmayr. The material seen by Zimmer and most of the important specimens of Hellmayr were combined for this study, in addition to material of recent origin not seen by Zimmer or Hellmayr"--P. [1].