down feather structure varies between low‐ and high‐altitude torrent ducks (Merganetta armata) in the Andes

Rebecca G. Cheek, Luis Alza, Kevin G. McCracken

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


∙ Feathers are one of the defining characteristics of birds and serve a critical role in thermal insulation and physical protection against the environment. Feather structure is known to vary among individuals, and it has been suggested that populations exposed to different environmental conditions may exhibit different patterns in feather structure. We examined both down and contour feathers from two populations of male Torrent Ducks (Merganetta armata) from Lima, Peru, including one high‐altitude population from the Chancay‐Huaral River at approximately 3500 m a.s.l. and one low‐altitude population from the Chillón River at approximately 1500 m a.s.l.. Down feather structure differed significantly between the two populations. Ducks from the high‐altitude population had longer, denser down compared with low‐altitude individuals. Contour feather structure varied greatly among individuals but showed no consistent difference between populations. These results suggest that the innermost, insulative layer of plumage (the down), may have developed in response to lower ambient temperatures at high elevations. The lack of observable differences in the contour feathers may be due to the fact that this outer plumage layer is more important as waterproofing than insulation.

Original languageEnglish (US)
Pages (from-to)27-35
Number of pages9
JournalOrnitologia Neotropical
StatePublished - 2018


  • Andes
  • Contour feather
  • Down feather
  • Feather structure
  • Merganetta armata
  • Peru
  • Temperature variation
  • Torrent Duck

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology


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