SPECIES

Black-and-chestnut Eagle Spizaetus isidori Scientific name definitions

Tomás Rivas-Fuenzalida, Juan M. Grande, Sebastián Kohn, Felix Hernán Vargas, and Santiago Zuluaga Castañeda
Version: 2.0 — Published November 23, 2022

Diet and Foraging

Feeding

Microhabitat for Foraging

It has been observed hunting mainly in the open tree canopy of primary forest (27, TRF unpublished data), but most attacks on chickens occur in open land (ex: pastures, roads, etc.) surrounded by forests (TRF, unpublished data). Hunting attempts high over the tree canopy have also been observed (TRF, unpublished data).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 It also hunts while soaring, ending with a dive into the canopy to catch arboreal mammals and birds (27, TRF, unpublished data).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Hawk (Rupornis magnirostris) and Hook-billed Kite (Chondrohierax uncinatus), in dive flights while soaring (TRF, unpublished data; Daniel Orizano, personal communication). Attacks on poultry usually occur when foraging through open areas, near houses, or in newly tilled fields (TRF, unpublished data).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seems that adults also partially clean the nests, as few remains are usually found at the nest or below it (JMG et al., unpublished data).

Diet

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, 37, 49); see also Table 1. It has also been observed consuming domestic fowl relatively often (48, 37, 49, Rivas-Fuenzalida et al., unpublished data).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persecuted by humans, particularly at sites where their nests are near human habitation (51, Rivas-Fuenzalida et al., unpublished data; see Conservation).

Quantitative Analysis

According to Restrepo-Cardona et al. (49), 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).

Food Selection and Storage

Information needed.

Nutrition and Energetics

Information needed.

Metabolism and Temperature Regulation

Information needed.

Drinking, Pellet-Casting, and Defecation

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.

Recommended Citation

Rivas-Fuenzalida, T., J. M. Grande, S. Kohn, F. H. Vargas, and S. Zuluaga Castañeda (2022). Black-and-chestnut Eagle (Spizaetus isidori), version 2.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.baceag2.02