Diet and Foraging

Microhabitat for Foraging

It has been observed hunting mainly in the open tree canopy of primary forest (27 Valdez, U., and S. Osborn (2004). Observations on the ecology of the black-and-chestnut eagle (Oroaetus isidori) in a montane forest of southeastern Peru. Ornitología Neotropical 15:31-40. Close , TRF unpublished data), but most attacks on chickens occur in open land (ex: pastures, roads, etc.) surrounded by forests (TRF, unpublished data). Hunting attempts high over the tree canopy have also been observed (TRF, unpublished data).

Food Capture and Consumption

Black-and-chestnut Eagle hunts from a perch, with a sit-and-wait technique, typical for large eagles and hawks. It uses its weight to gain speed in dive flight, surprising its prey. It also hunts while soaring, ending with a dive into the canopy to catch arboreal mammals and birds (27 Valdez, U., and S. Osborn (2004). Observations on the ecology of the black-and-chestnut eagle (Oroaetus isidori) in a montane forest of southeastern Peru. Ornitología Neotropical 15:31-40. Close , TRF, unpublished data). The eagle attacks other raptors, such as Roadside Hawk (Rupornis magnirostris) and Hook-billed Kite (Chondrohierax uncinatus), in dive flights while soaring (TRF, unpublished data; Daniel Orizano, personal communication). Attacks on poultry usually occur when foraging through open areas, near houses, or in newly tilled fields (TRF, unpublished data). Adults usually deliver partially consumed prey to the nest, and only very rarely is the whole prey seen there. For example, in Argentina, of 34 prey taken to the nest, only one Red-faced Guan (Penelope dabbenei) was taken whole. It seems that adults also partially clean the nests, as few remains are usually found at the nest or below it (JMG et al., unpublished data).

Major Food Items

Preys mainly on medium-sized birds and arboreal mammals. Usual prey items include birds, such as guans (Penelope sp., Chamaepertes sp., Ortalis sp.) and pigeons (Patagioenas sp.); mammalian prey includes squirrels (Sciurus sp.), opossums (Didelphis sp.), coatis (Nasua sp.), and monkeys (Cebus spp.) (48 Zuluaga, S., and M. Á. Echeverry‐Galvis (2016). Domestic fowl in the diet of the Black‐and‐chestnut Eagle (Spizaetus isidori) in the eastern Andes of Colombia: a potential conflict with humans? Ornitología Neotropical 27(1):113–120. 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 , 49 Restrepo-Cardona, J. S., C. Márquez, M. A. Echeverry-Galvis, F. H. Vargas, D. M. Sánchez-Bellaizá, and L. M. Renjifo (2019). Deforestation may trigger Black-and-chestnut Eagle (Spizaetus isidori) predation on domestic fowl. Tropical Conservation Science 12:1-10. Close ); see also Table 1. It has also been observed consuming domestic fowl relatively often (48 Zuluaga, S., and M. Á. Echeverry‐Galvis (2016). Domestic fowl in the diet of the Black‐and‐chestnut Eagle (Spizaetus isidori) in the eastern Andes of Colombia: a potential conflict with humans? Ornitología Neotropical 27(1):113–120. 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 , 49 Restrepo-Cardona, J. S., C. Márquez, M. A. Echeverry-Galvis, F. H. Vargas, D. M. Sánchez-Bellaizá, and L. M. Renjifo (2019). Deforestation may trigger Black-and-chestnut Eagle (Spizaetus isidori) predation on domestic fowl. Tropical Conservation Science 12:1-10. Close , Rivas-Fuenzalida et al., unpublished data). For this reason, the species is heavily persecuted by humans, particularly at sites where their nests are near human habitation (51 Restrepo-Cardona J. S., M. A. Echeverry-Galvis, D. L. Maya, F. H. Vargas, O. Tapasco, and L. M. Renjifo (2020) Human-raptor conflict in rural settlements of Colombia. PLoS ONE 15(1):e0227704. Close , Rivas-Fuenzalida et al., unpublished data; see Conservation).

Quantitative Analysis

According to Restrepo-Cardona et al. (49 Restrepo-Cardona, J. S., C. Márquez, M. A. Echeverry-Galvis, F. H. Vargas, D. M. Sánchez-Bellaizá, and L. M. Renjifo (2019). Deforestation may trigger Black-and-chestnut Eagle (Spizaetus isidori) predation on domestic fowl. Tropical Conservation Science 12:1-10. Close ), at four locations in Andean Colombia, the percentage of birds in the diet delivered to nestlings ranged from 30.6% to 57.1%, while mammals delivered ranged from 25.5% to 49.1%. Reptiles were represented by only one snake species at two sites (8% and 12% of total prey items, respectively). Bird biomass ranged from 27.7% to 63.8% of the total biomass delivered to nests, and mammal biomass ranged from 36% to 69.6%. In Argentina, 100% of the recorded prey items were birds, with a high proportion of guans (Penelope sp.), but also including domestic fowl and other raptors (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 ).

Information needed.

Information needed.

Information needed.

Not studied. Probably drinks water in small mountain rivers surrounded by forests. Pellets not measured. Defecates while perched (usually), and in flight (rarely); in typical raptor fashion when perched, ejects feces powerfully.