First record of a nest and successful reproduction of the Black-and-white Hawk-eagle (Spizaetus melanoleucus) for Argentina

Abstract

Studying nesting sites is especially important for understanding the habitat requirements and behavior of species and planning efficient conservation strategies. We performed a bibliographic search of the locations of all known nests of the Black-and-White Hawk-eagle (Spizaetus melanoleucus) in the Americas. We report the first active nest with successful reproduction for this species in Argentina. The first nest for the species was discovered in Panamá in 1972, while the first complete description was made 36 years later in Brazil. We found a total of 17 known nests to date. The nesting platform found in Argentina was discovered in the Salto Encantado Provincial Park in the province of Misiones in October 2019. On October 13, 2022, we found a 20-25-day-old chick and an adult female inside the nest, which was constructed in a 25-m-tall tree (Aralia warmingiana) in a valley with a steep slope, setting it apart from the canopy. During the following monitoring, in November 2022, the 60-day-old chick was observed flying with its parents among the nearby trees. The discovery of this nesting site emphasizes the importance of taking direct conservation measures. The study of environmental variables at the site and the reproductive behavior of these individuals will generate important information for improving the detection of sites of interest and proposing efficient conservation strategies for this threatened species.