Conquistando o ambiente urbano: valor adaptativo e comportamento parental nos ninhos de Turdus leucomelas (Aves, Turdidae) em edifícios

Abstract

Reproduction is a crucial stage of the life cycle of all species, and the related energetic conflicts are especially important on species that present intense parental care, such as altricial birds. Nest site selection is directly linked to adult fitness by potentially minimizing the costs of offspring rearing and predation risk for both adults and young. However, the influence of anthropogenic environments on bird behavior and reproduction is still poorly known. Here, I address the effect of trees and buildings as nesting substrates on the incubation behavior and clutch survival in the Pale-breasted Thrush (Turdus leucomelas). I also assess the causes and consequences of mate change and nest reuse, and the relationship between the use of buildings as nesting substrates and female personality. Clutches on buildings had higher success due to a protective effect of buildings during the egg phase. The internal temperature of nests was higher on buildings, creating a compensatory effect for the incubation recesses took by females along the daytime. Consequently, females of nests on buildings showed lower nest attentiveness due to longer incubation recesses. I also found that pairs that stayed together had higher chance of nest reuse, and produced more fledglings. Nests were more often reused after a successful clutch, especially within the same breeding season. Nest reuse, in turn, enhanced earlier clutches at the beginning of the breeding season, and reduced the chance of brood parasitism by the Shiny Cowbird (Molothrus bonariensis). Finally, female personality differed between nesting support types, with those that nested on buildings were less neophobic. The results suggest that pairs that nest on buildings may have a higher fitness, by either lower incubation costs and higher clutch survival, the last also related to the increased chances of nest reuse and its advantages. Additionally, the difference on the personality of females that nested on buildings indicates that the advantages of exploiting that anthropogenic resource are dominated by a specific subset of the population. In conclusion, the use of buildings as nesting substrates increase the breeding performance of our study species in the urban environment in multiple ways, contributing to the adaptation of this species to this environmental context.