Notes on the reproduction of the Ultramarine Grosbeak Cyanoloxia brissonii in northeastern Brazil

Abstract

We conducted a study of 21 nests of the Ultramarine Grosbeak Cyanoloxia brissonii between May 1986 and April 2018 in the state of Alagoas in northeastern Brazil. Most of our observations were made during the rainy season, particularly in April and May, with additional data gathered at the beginning and end of the season.

The clutch size averaged 2.06 eggs per nest. The eggs measured an average of 20.7×15.7 mm and weighed c. 2.6 g. Both parents shared incubation duties, with an incubation period averaging 13 days. The nestling period was 13–14 days.

Although Ultramarine Grosbeaks typically breed in secondary forests, clearings, and forest edges, we noticed a decline in the local population during the study period. We believe this decline is linked to factors such as capture for cage breeding, illegal wildlife trafficking and the widespread use of pesticides, all of which probably affect the survival of Ultramarine Grosbeak and other seed-eating birds in the region.

There is limited information in the literature about the reproductive biology of Ultramarine Grosbeak; thus, the information presented here contributes to a deeper understanding of the biology of the species. We hope that it will also help to guide conservation efforts for both the Ultramarine Grosbeak and its habitat.

Keywords: Reproductive biology, eggs, incubation, chicks, Grosbeak, north-east Brazil.