Oecologia

, Volume 174, Issue 3, pp 689–698

Synchronizing feather-based measures of corticosterone and carotenoid-dependent signals: what relationships do we expect?

  • Graham D. Fairhurst
  • Russell D. Dawson
  • Harry van Oort
  • Gary R. Bortolotti
Physiological ecology - Original research

DOI: 10.1007/s00442-013-2830-5

Cite this article as:
Fairhurst, G.D., Dawson, R.D., van Oort, H. et al. Oecologia (2014) 174: 689. doi:10.1007/s00442-013-2830-5

Abstract

Carotenoids produce many of the red, orange and yellow signal traits of birds, and individuals must trade off utilizing carotenoids for physiological processes versus ornamentation. Proximate mechanisms regulating this trade-off are poorly understood, despite their importance for expression of color signals. Corticosterone (CORT) may play a significant mechanistic role in signal expression because it mobilizes energy substrates and influences foraging behavior. We used a unique feather-based approach to test whether CORT mediates expression of carotenoid-based coloration. First, we investigated relationships between levels of CORT from feathers (CORTf) and carotenoid-based plumage signals in common redpolls (Acanthis flammea). Then, we determined how the width of growth bars and probability of having fault bars on feathers varied with CORTf, specifically whether these metrics reflected developmental costs of elevated CORT (“stress” hypothesis) or represented an individual’s quality (“quality” hypothesis). CORTf correlated positively with the strength of carotenoid signals, but only in adult males. However, also in adult males, CORTf was positively related to width of feather growth bars and negatively with probability of having fault bars, providing support for the quality hypothesis. Overall, CORTf was lower in adult males than in females or young males, possibly due to dominance patterns. Our results indicate that CORT may indirectly benefit feather quality, potentially by mediating the expression of carotenoid signals. We place our sex-specific findings into a novel framework that proposes that the influences of CORT in mediating carotenoid-based plumage traits will depend on the extent to which carotenoids are traded off between competing functions.

Keywords

Acanthis flammea Carotenoid-dependent plumage color Common redpoll Corticosterone Feather quality 

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Graham D. Fairhurst
    • 1
  • Russell D. Dawson
    • 2
  • Harry van Oort
    • 3
  • Gary R. Bortolotti
    • 1
  1. 1.Department of BiologyUniversity of SaskatchewanSaskatoonCanada
  2. 2.Ecosystem Science and ManagementUniversity of Northern British ColumbiaPrince GeorgeCanada
  3. 3.Cooper Beauchesne and Associates LimitedRevelstokeCanada

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