Plumage Reflectance and the Objective Assessment of Avian Sexual Dichromatism

• DOI: 10.2307/2463580
• Publication Date: 2017-01-06T01:52:00Z
• Authors: Cuthill; Bennett; Partridge; Maier
• Keywords: Plumage; Iridescence; Sexual dimorphism

Assessment of color using human vision (or standards based thereon) is central to tests many evolutionary hypotheses. Yet fundamental differences in between humans and other animals call this approach into question. Here we use techniques for objectively assessing patterns that avoid reliance on species‐specific (e.g., human) perception. Reflectance spectra are the invariant features expect animal's cognition have evolved extract. We performed multivariate analyses principal components derived from >2,600 reflectance (300–720 nm) sampled a stratified random design different body regions male female starlings breeding plumage. Starlings possess spatially complex plumage extensive areas iridescence. Our study revealed previously unnoticed sex coloration nature iridescent noniridescent differences. Sex occurred some but not others, were more pronounced at wavelengths (both ultraviolet visible), involved mean spectral shape. Discriminant analysis sufficient correctly 100% our sample. If hidden sexual dichromatism widespread, then it has important implications classifications as mono‐ or dimorphic taxonomic conservation purposes.