Sex, age, mean annual temperature and year predict the body condition in Chiroxiphia caudata (Passeriformes: Pipridae)

The body condition is an important metric for measuring an individuals’ morphological, biochemical, and physiological status. It may be influenced by several factors, such as the incidence of parasites, age, sex and climate. Therefore, we aimed to study the relationship between body condition, measured through the scaled-mass index, climate, altitude, sex, and age in Chiroxiphia caudata . We gathered data collected from 2001 to 2017, in five different Brazilian states: Santa Catarina, Paraná, Minas Gerais, São Paulo and Rio de Janeiro. We found that juvenile males had an increased body condition when compared to females, whereas when they reached adulthood, this relationship is inverted with females having a much higher scaled-mass index (SMI) compared to males. We also found a significant tendency of the SMI to decrease over time, and we suggest that such happening may be related to extreme and frequent events taking place in the region, such as intense droughts, habitat loss and the expansion of the agricultural land use. Finally, we found that the mean annual temperature exhibited a negative relationship with variation in SMI. Therefore, individuals coming from colder places needed to have an extra layer of fat to cope with the cold. In conclusion, our results show important within species variability, which may direct conservation effort priorities and raise consciousness for other researchers using publicly available data, since there should be an inherent spatial–temporal variability.