Cuidado parental do Chororó-do-Pantanal Cercomacra melanaria (Ménétriès, 1835) (Aves : Thamnophilidae)

Abstract

Parental care can be defined as characteristics coming from the parents that lead to an increase in the fitness, survival, growth, and quality of offspring without considering costs. When it comes to parental investment these costs are considered. The benefits for the offspring can incur in costs to the parents in time, energy, survival, and mating opportunities with other partners. This study aims to describe the parental care behavior of Cercomacra melanaria, comparing the parental investment between female and male in the main activities. It is expected that there will be no difference in the behaviors of nest building, incubation, and brooding, however it is expected that there will be a difference in relation to the daytime, with males contributing more at the morning and females contributing more at the afternoon. It is expected that C. melanaria males contribute more than females in nest defense. The study took place in Pantanal, at Fazenda Retiro Novo, district of Pirizal, municipality of Poconé, Mato Grosso, Brazil. The behaviors considered were transporting building material, building nest, incubation, brooding, feeding of nestlings and removal of the fecal sacs. Nest defense was collected during all stages. Transporting building material, nest building and removal of the fecal sacs weren’t analyzed quantitatively. Males incubated and defended the nest more than females. There was a difference in the incubation rate between sexes in relation to the daytime, males incubated more than females in the morning and in the afternoon as well. There was no difference between males and females in brood and feeding of nestlings. The greatest contribution of males in the morning was expected, since the males replacing the females in the morning is common, however it was also found that males incubate more in the afternoon, which suggests that males invest more than females in daytime incubation. These results are consistent with the hypothesis that females may need more foraging time to replenish or maintain energy levels after laying eggs. In this study, we could observe the differences between males and females of C. melanaria in parental care activities, giving evidence to a large participation of males in nest defence and incubation. This study provides a direction for future projects to progress in understanding the sexual role of males and females of the species in parental care and agonistic behaviors such as defending territories, sexual partners, and offspring.