Implicações da muda, reprodução e precipitação pluviométrica na condição corporal de aves na Caatinga

Abstract

The availability of rainfall in semiarid environments have an important role in the periods of molting and breeding of birds in the region. The rains provide in semiarid regions a high availability of food resources for all trophic groups. These resources are of great importance for the birds to be able to maintain their energy reserves and maintain a good body condition to carry out their life stages efficiently. The objective of this study was to evaluate how the body condition of Caatinga birds is influenced by the molting and breeding periods precipitation related and how these variables affect different trophic categories. The bird richness and abundance data were collected around the Itaparica Reservoir, in the municipalities of Petrolândia in the state of Pernambuco, and Glória and Rodelas in Bahia. Our results indicate that precipitation has a positive relationship on the increase in body condition in dry environments. A total of 46.9% of the captured individuals presented negative Relative Mass Index values. As for the results of the community models, the countour feathers influenced negatively the of birds RMI, while the isolated effect of precipitation was positive for the birds. The incubation patch four appeared to be favorable to increasing the RMI of birds in community models. When was considering species according to their trophic category, the granivorous and insectivorous species showed similar results, with positive results on their RMI when there was an interactive effect between precipitation and molts of remiges and rectrices. Omnivorous species were positively affected by the effect of precipitation, showing an important factor also when considering the incubation patch. This research attests to the importance of precipitation for good body condition and indicates an indirect effect linked to factors correlated to rain in dry environments, such as food availability for different trophic categories.