Breeding success of Buff-necked ibis (Theristicus caudatus) (Pelecaniformes: Threskiornithidae) in Araucaria Plateau, Rio Grande do Sul, Brazil

Abstract

The life history of a species can be considered the main source of information about it, parameters such as incubation period, number of eggs and chicks, may represent the aptitude of individuals in relation to the environment, modified or not. Thus information from the reproductive success of a species allows evaluating the relationship of individuals to environmental changes. This study aimed to assess the reproductive success of three different populations of Buff-necked ibis, Theristicus caudatus, in Araucaria Plateau. The groups were followed in the reproductive season of 2011, three breeding which had environmental characteristics different from each other. We used three methods to determine the reproductive success: apparent success, hatching rate of eggs and protocol of Mayfield. In 600 hours of observation during the reproductive period, approximately 200 hours for each group, there was an average of 1.87 ± 0.74 eggs per nest. The apparent success and the protocol of Mayfield showed proportional differences between the groups. The environment where individuals were nesting in group B can be considered a compromise between the characteristics of other groups, with anthropogenic characteristics that draw predators away from nests and feeding areas, while feeding sites has reduced external influences.