Rufous Common Cuckoo chicks are not always female

0492290 - ÚBO 2020 RIV DE eng J - Článek v odborném periodiku
Koleček, Jaroslav - Šulc, Michal - Piálková, Radka - Troscianko, J. - Požgayová, Milica - Honza, Marcel - Procházka, Petr
Rufous Common Cuckoo chicks are not always female.
Journal of Ornithology. Roč. 160, č. 1 (2019), s. 155-163. ISSN 2193-7192. E-ISSN 2193-7206
Grant CEP: GA ČR(CZ) GA17-12262S
Institucionální podpora: RVO:68081766
Klíčová slova: Avian vision * Colour dimorphism * Cuculus canorus * Molecular analysis * Plumage colouration * Spectral reflectance
Obor OECD: Ornithology
Impakt faktor: 1.286, rok: 2019
Způsob publikování: Omezený přístup
http://dx.doi.org/10.1007/s10336-018-1591-7

The Common Cuckoo (hereafter Cuckoo) shows two adult plumage morphs—adult male plumage is grey and adult females are either grey or, less frequently, rufous. The situation is less clear in juveniles, as both sexes exhibit variable proportions of grey and rufous colour. We thus describe the patterns related to sex-specific plumage colour variation in a central European Cuckoo population. We genetically determined the sex of 91 Cuckoo chicks and using visual classification of photographs we scored juvenile plumage colouration of individual chicks into five classes based upon the increasing proportion of rufous colour on feathers. To verify these scores, we sampled chick feathers and quantified the proportion of rufous colour of individual feathers by digital image analysis. We found that juvenile females had a higher proportion of rufous colour of feathers than juvenile males. However, the difference was marginally non-significant based on visual inspection alone, and some male chicks even showed intensively rufous plumage like those of juvenile females. In contrast, we captured only grey adult males (n = 37), while five out of 20 adult females were rufous. The rufous colour of Cuckoo feathers considerably differed from the grey colour and the difference seemed to be larger in adults than in juveniles. We show that chicks, unlike adult females, cannot be visually assigned to either of the adult morphs. Therefore, we encourage further investigation of Cuckoo plumage colouration across the species’ range to examine the process of plumage maturation. A detailed genetic analysis is necessary to understand the origin of Cuckoo feather colouration.
Trvalý link: http://hdl.handle.net/11104/0285815