Breeding biology of the Blue-crowned Parakeet in the Caatinga dry-forest of northeast Brazil

The Blue-crowned Parakeet (Thectocercus acuticaudatus haemorrhous) occurs throughout the interior of the semi-arid Northeast Brazil and is not classified as an endangered sub-species. Little is known about its breeding biology, especially when nesting in rock cavities. The present work describes breeding aspects of a Blue-crowned Parakeet population from the Caatinga dry-forest of Canudos, Bahia state. The study was conducted using direct observation and rappel techinics to access the natural cavities used as nests in the cliffs found in Estação Biológica de Canudos between 2011 and 2017. Eight active cavities were measured and eighteen reproductive events monitored. Cavities used as nest had an internal design of gallery with single or multiple tunnels; we observed clutches with 3 (n=4) or 4 (n=6) white short-oval eggs. We measured width (26.27±1.04, range 23.90 – 27.54 cm), length (32.70±1.03, range 30.51 – 34.30 cm) and weight (11.8 ± 0.43, range 11.2 – 12.3) of 13 eggs. Four nests were used during up to six consecutive years. Typical breeding season lasted from January to April, but depending on the irregular rain precipitation in the region, reproduction started earlier in December or as later as in April. Cavities used as nest by parakeets were also used for reproduction by Lear´s Macaws (Anodorhynchus leari), Blue-fronted Parrot (Amazona aestiva) and Barn Owl (Tyto furcata). Our study presents the first data on Blue-crowned Parakeet‘s breeding biology in Brazil and the novel information of rock cavity being used as reproductive site.