Carotenoid-based plumage coloration reflects hemoparasite infection and local survival in breeding great tits

Carotenoid-based sexual coloration has been hypothesised to be prevalent ac ross many vertebrate taxa because it reliably reflects individual phenotypi c quality in terms of foraging efficiency or health status due to the trade -off between signal colour and use of carotenoids for immune function and d etoxification. We investigated the ventral, yellow coloration of breeding a dult great tits (Parus major L.) in relation to sex, age, breeding habitat, local survival and infection status with respect to Haemoproteus blood par asites. The extent of plumage coloration (estimated as hue and lutein absor bance) was generally higher in rural than in urban birds. Males had higher values of hue than females. In both male and female yearlings, the plumage of unparasitised individuals had a greater hue of yellow than parasitised o nes, while older males revealed the opposite pattern. The survival of infec ted yearlings was worse than that of uninfected yearlings, while the opposi te was true for old breeders. Survivors had generally higher values of hue than nonsurvivors. These results are consistent with predictions of functio nal hypotheses, suggesting that carotenoid-based plumage coloration serves as a signal reflecting individual quality in terms of health status and loc al survival.