Anidación del búho campestre (Asio flammeus bogotensis) en la Sabana de Bogotá, Colombia

Nesting of the Short-eared Owl (Asio flammeus bogotensis) in the Sabana de Bogotá, Colombia

Abstract

Reproduction is one of the most important aspects of a species biology. However, this information is scarce for nocturnal species such as owls, for which we do not know basic details of the natural history, particularly of species with a Neotropical distribution. The Short-eared Owl (Asio flammeus) is a widely distributed species, the little that is known about its reproductive biology has become a generalized statement from studies in temperate zones. We made observations of three reproductive events of the Short-eared Owl in the Bogotá Savannah between 2014 and 2018. We include data on habitat, nest architecture, eggs, chicks, juveniles and adults description, determination of vocalizations and diet description through the analysis of 18 pellets. Asio flammeus bogotensis nests on the ground, in open areas such as grasslands, with an average clutch size of two white and rounded eggs (n = 3). The nestlings were born with cream-colored down, eyes closed and unable to move until the seventh day after hatching. They were cared for by both adults for at least three months after they left the nest. We identified six types of vocalizations with frequencies below 8 KHz and average wave amplitudes of 3 KU, apparently related to developmental status and behaviors. Regarding the diet we found 136 food items, including insects (beetles and odonates) 61.76%, small mammals (rodents and shrews) 33.82%, and birds (pigeons and passerines) 4.42%. The predominant prey were Coleoptera (Ancognatha vulgaris) and the common mouse (Mus musculus). There are still several aspects of the natural history of this and other species that we hope will continue to be studied by ornithologists in the Neotropics.