Immature but not cryptic plumage in males of the Saffron Finch Sicalis flaveola pelzeni

BENÍTEZ SALDÍVAR, M. J.; PALMERIO, A.G; MASSONI VIVIANA

Princeton

Congreso; 51st Annual Conference of the Animal Behavior Society; 2014

Animal Behavior Society and Princeton University

Saffron Finches have delayed plumage maturation resulting in ?white? immature plumaged and yellow mature plumaged males. White males are capable of reproducing after one year of age and, to humans, are indistinguishable from females. We compared the coloration of five regions of 29 females and 9 white males nesting in Chascomus, Argentina (2008-2010), using a reflectance spectrometer. The first two components of the PCA explained, on average, 89% of the variation in all body regions. The PC1 showed positive loadings below 470-530nm and negative loadings in the rest of the spectra. White males and females differed significantly at the blue chroma of the forehead, and the Vorobyev-Osorio model of visual discrimination showed values of just noticeable differences (jnd) greater than one in all regions. White males and females showed values greater than 3 jnds in chromatic and achromatic components in lower scapulars and breast. These results indicate that the two groups can recognize each other based on their color. White males can, therefore, be detected by conspecifics and they could be potential targets of intrasexual aggression from yellow males, even when not singing.