Movements and Migration

Little studied. Breeding adults are sedentary and their home range can exceed 3,000 ha (SZ and JMG, unpublished data). A juvenile during the post-fledging period remained near the nest, occupying an area of 48.1 ha, until it was independent (40 Zuluaga, S., J. M. Grande, D. F. Aristizábal, and G. Guevara (2018). Parental dependence of a juvenile Black-and-chestnut Eagle (Spizaetus isidori) in the eastern Andes, Colombia. Ornitología Neotropical 29:153–158. Close ). Six juveniles captured and tagged between 2015–2020 in Colombia and Argentina had large home ranges (mean ~1,000 km²) during their natal dispersal through fragmented landscapes (50 Zuluaga, S., F. H. Vargas, R. Aráoz, and J. M. Grande (2022). Main aerial top predator of the Andean Montane Forest copes with fragmentation, but may be paying a high cost. Global Ecology and Conservation 37(2022):e02174. Close ). An immature tracked for four years (between 2015 and 2019) in eastern Colombia established its own territory when it was about three years old, approximately 20 km from its nest (SZ, unpublished data).

Natal Philopatry and Dispersal

Juveniles begin to disperse at around eight months old (40 Zuluaga, S., J. M. Grande, D. F. Aristizábal, and G. Guevara (2018). Parental dependence of a juvenile Black-and-chestnut Eagle (Spizaetus isidori) in the eastern Andes, Colombia. Ornitología Neotropical 29:153–158. Close ). During natal dispersal, the home range of immature birds can reach up to 200,000 ha, and juvenile birds can move up to 60 km from the nest (50 Zuluaga, S., F. H. Vargas, R. Aráoz, and J. M. Grande (2022). Main aerial top predator of the Andean Montane Forest copes with fragmentation, but may be paying a high cost. Global Ecology and Conservation 37(2022):e02174. Close ). As young birds disperse, they may settle temporarily in an area where they spend several weeks to a few months before moving on to other areas. During this period, some juveniles may also visit their natal nest (notably when around one year old), from which they are expelled by the adults (Zuluaga et al., unpublished data).

Fidelity to Breeding Site

Nests are reportedly reused annually (14 Lehmann, F. C. (1959). Contribuciones al estudio de la fauna de Colombia XIV. Nuevas observaciones sobre Oroaetus isidori (Des Murs). Novedades Colombianas 1:169–195. Close , 37 Aráoz, R., J. M. Grande, C. López, J. Cereghetti, and F. H. Vargas (2017). The first Black-and-Chestnut Eagle (Spizaetus isidori) nest discovered in Argentina reveals potential human-predator conflicts. Journal of Raptor Research 51(1):79–82. Close , Rivas-Fuenzalida et al., unpublished data), but may also be abandoned after a season and then reused some years later (SK, unpublished data).