When to measure plumage reflectance: a lesson from Collared Flycatchers Ficedula albicollis

Gergely Hegyi, Miklós Laczi, Nóra Boross, Mónika Jablonszky, Dóra Kötél, Katalin Krenhardt, Gábor Markó, Gergely Nagy, Balázs Rosivall, Eszter Szász, László Zsolt Garamszegi, János Török

Research output: Contribution to journalArticle


Sexually selected colour traits of bird plumage are widely studied. Although the plumage is replaced only at one or two yearly moults, plumage colour has long been shown to change between moults. Nevertheless, most studies measure colour weeks to months after the courtship period, typically at nestling rearing, and it is unclear whether these measurements yield relevant data concerning the primary process of sexual selection. Here we analyse repeated spectrometric data taken from male Collared Flycatchers during social courtship and nestling rearing. We show that some spectral traits are not correlated between the two measurements and that within-individual correlation declines significantly with the likely exposure of the plumage area to damage and soiling. There is an overall decline in spectral trait exaggeration during breeding, but trait decline is not closely related to measurement latency, especially not in the damage-exposed areas. Finally, sexual selection estimates differ depending on whether they are derived from spectra measured during courtship or during nestling rearing. These results suggest that, contrary to current practice, measurements of plumage reflectance should be made during the primary period of sexual signalling. Spectral trait decline during breeding could also be studied as a possible signal for mates and neighbours.

Original languageEnglish
Pages (from-to)27-34
Number of pages8
Issue number1
Publication statusPublished - Jan 2019


  • brightness
  • chroma
  • sexual selection
  • signal deterioration
  • spectrometry

ASJC Scopus subject areas

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

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    Hegyi, G., Laczi, M., Boross, N., Jablonszky, M., Kötél, D., Krenhardt, K., Markó, G., Nagy, G., Rosivall, B., Szász, E., Garamszegi, L. Z., & Török, J. (2019). When to measure plumage reflectance: a lesson from Collared Flycatchers Ficedula albicollis. Ibis, 161(1), 27-34. https://doi.org/10.1111/ibi.12609