Reproduction of Blue-black Grassquits in central Brazil

Abstract

During the reproductive season Blue-black grassquit (Volatinia jacarina) males are found in clusters, wherein they exhibit a distinctive display that consists of repeated, vertical leaps while simultaneously producing a brief vocalization. The main objective of this study was to describe details of the species' reproductive behavior in a "Cerrado" area of central Brazil and compare these data with some studies carried out in other areas. The data obtained concerning different aspects of nesting, laying and hatching were generally similar to those obtained in previous studies in other areas. However, we found that the typical clutch size of two eggs per nest is lower, and egg and nestling mortality rates higher in our area than what has been reported elsewhere. Our results suggest that males differ in time expended with different activities according to their reproductive condition and also provide extensive parental care. We found that display execution rates peak in the early morning and in the late afternoon and are higher in the middle of the breeding season. We also found that there is an inverse relation between the height of the display leap and the height of the perch.