Weather is known to affect the phenology and behaviour of birds, but weather-related changes of phenotypic traits involved in communication have received little attention. Using an eight-year data set, we investigated links between carotenoid-based reflectance of the freshly moulted breast of Great Tits Parus major, weather during the moulting period, food availability during the preceding breeding season, and we investigated inter-annual changes. In both sexes, we found change of colour expression to more saturated and darker yellow in both sexes over the study period in parallel with increasingly dry and warm weather during moult. These results indicate that the expression of traits playing roles in communication may be controlled by weather and may therefore shift in response to changing climate.
Laczi, M., Hegyi, G., Nagy, G., Pongrácz, R., Török, J. (2019). Yellow plumage colour of Great Tits Parus major correlates with changing temperature and precipitation. Ibis (DOI: 10.1111/ibi.12761)