Breeding patterns and habitat use in the endemic Curl-crested Jay of central Brazil

Abstract

Little is known about the life history and reproduction of the Curl-crested Jay (Cyanocorax cristatellus), despite its conspicuousness and endemic status, being restricted primarily to the central Cerrado biome of Brazil. From May 1999 to December 2000, we examined the sizes of home ranges and foraging and reproductive patterns in this species. Average group size was approximately 10 individuals, with average home ranges of 172 ha; during the reproductive period individuals in the group tended to stay within approximately 29 ha of active nests. These jays are dietary generalists, while the diversity of substrates and capture techniques employed showed high flexibility in resource utilization. The reproductive period was from September to March, and groups produced average clutch sizes of 5.7 eggs, but only 35% of these hatched and only 25% of the nests produced at least one fledgling. Predation was the chief cause of nesting failure, accounting for 63% of nest loss. The occurrence of large groups year-round with several individuals providing parental care and evidence of just one female laying eggs suggest that the Curl-crested Jay is a cooperative breeder with a high degree of sociality. However, further study is necessary to exclude the possibility that more than one female is laying eggs in a single nest.