Offspring plumage colouration as a condition-dependent signal in the blue tit

Datasets: 1. Nestling dataset contains a dataset of individual data of nestlings sampled during three consecutive breeding seasons. <br> 2. Nest dataset contains a dataset of the mean values of nestlings per nest (mean of the variables of the nestlings raised in the same nest) during three consecutive breeding seasons. nestling colouration, quality, honest signalling, condition dependence, UV colouration, sex differences, carotenoids