Home range and reproductive biology of Bubo virginianus at brazilian Pampa

Bubo virginianus is widely distributed in the Americas. Although relatively common, several aspects of the natural history of this owl remain unknown, especially in the Neotropical region. The aim of this study is to contribute to better understand the ecology of this species in the Pampa Biome. The study was conducted between 2015 and 2017 in Brazilian Pampa, Rio Grande do Sul, Brazil. A pair of great horned owls and their offspring was monitored along two reproductive seasons (monthly based observations). The location of each individual was taken with a GPS and used to calculate the home range estimates, which were performed using the software Biotas. The nestling period lasted for three months in both reproductive seasons. The post-fledging dependency period lasted for six months. In both reproductive periods clutch size was two eggs. In 2015 two youngs were successful raised. In 2016 just one egg hatched and this young was successful raised. Considering 95% of locations (excluding outliers points), home range of the pair of great horned owl was estimated as 0.35 km² considering MCP method, or 0.41 km² considering Kernel estimates. The monitored individuals spent the night in the border of the territory, using the central area of territory for resting during daytime. The breeding season seems to be associated to austral winter with hatching in late winter. The offspring seem to stay with the parents until beginning a new reproductive season, dispersing late in autumn.