Male achromatic wing colouration is related to body condition and female reproductive investment in a dichromatic species, the upland goose

In many bird species, achromatic plumage patch size can serve as a male status signal, but the use of variations in the achromatic colours themselves as a quality signal has only recently come into focus. In our study, we sought to determine whether achromatic plumage reflects individual quality in the upland goose (Chloephaga picta leucoptera). We examined the relationship between male head and wing reflectance, male condition and female reproductive investment.

Anja Gladbach et al, J Ethol (2011) 29:243-249