Sex- and age-related variation in survival and cost of first reproduction in greater flamingos

We analyzed survival of breeding Greater Flamingos, Phoenicopterus ruber ro seus, using the capture histories of 2000 breeding birds ringed as chicks a nd resighted at their natal colony in the Camargue, southern France. As fou nd in previous analyses, recapture probability varied according to year, se x, and age of the bird, and annual survival was strongly affected by winter severity. However, by using a much larger data set than in earlier analyse s, we detected previously nonsignificant effects. Indeed, for the first tim e, sex and age of the bird were found to influence annual survival probabil ity. We tested the hypothesis that the observed sex-related difference, in survival corresponded to asymmetric costs of reproduction. A model includin g a cost of first observed reproduction on survival in young females only p rovided the best fit to the data and explained the majority of the sex-rela ted difference in survival of birds <7 yr old. Because a cost of reproducti on may be partially masked by birds that have already bred undetected, we e stimated the proportion of experienced females among those observed breedin g for the first time. This proportion varied with the age of the birds and was used to calculate: the expected cost of early recruitment. Such a cost of early reproduction may have contributed to the evolution of deferred bre eding in females. Survival of experienced females was higher than that of m ales, with the difference being more pronounced in early age classes. Age h ad a significant positive effect on survival probability of birds.