Parabuteo unicinctus: variables ecológicas relacionadas con su nidificación en un ambiente urbano

The number of records that can be obtained for Parabuteo unicinctus in an urban environment at Ciudad Autónoma de Buenos Aires and its surroundings is remarkable. Therefore we studied this species in this area through direct observations, bibliographic data and personal communications of colleagues during November and December of 2016 with the aim of registering ecological variables related to its nesting. During both months, already known nesting sites were visited and new territories were found. Each time a nest was found, we registered: tree species, height (m), diameter at breast height (cm), presence/absence of the adults, number of nestlings, number of successful nestlings and the minimum distance between active nests (km). Three nests received assistance for nestlings falling out of them. We found a total of 10 nests, all in exotic trees for the ecoregion: Tipuana tipu (four), Casuarina sp. (three), Eucaliptus giganteus (two) and Acacia nigra (one). The average height was 21 m and average diameter at breast height was 0.82 m. Seven nests showed adult activity but in only four, at least one successful nestling was registered. Three of these latter nests later fell. Minimum distance between active nests was 1.65 Km. With this study, we confirm P. unicinctus as a resident and breeding species in the Metropolitan Area of Buenos Aires.