The crowned hawk-eagle is a formidable predator, capable of killing prey up to several times its own weight (2) (3). Primates usually make up the bulk of the diet (6) (11) (12), though other mammals are also taken, including small antelopes, rodents, hyraxes and mongooses, as well as large lizards, birds such as hornbills, guineafowl and pigeons, and occasionally carrion (2) (3) (12). The crowned hawk-eagle typically hunts by dropping onto prey from a perch, though it may also snatch tree-dwelling prey in flight, or knock it to the ground (2) (3). The largest prey is dismembered on the ground and pieces may be cached in nearby trees and eaten over several days (2) (3) (5). Crowned hawk-eagle pairs sometimes hunt co-operatively and will share cached food (3).
Courtship in the crowned hawk-eagle involves a noisy aerial display in which the bird, usually the male, performs a series of undulating dives and upward swoops. On being joined by the female, the male may dive, upon which the female rolls and the pair may lock talons and cartwheel through the air (3). Nesting season varies with location (2) (3), and the nest is usually built in the main fork of a large tree, although it may rarely be built on a cliff when no large trees are available (13). A massive structure, it may measure up to two and a half metres across and three metres deep, and is built with sticks and lined with sprays of green leaves. The breeding pair may use the same nest for many years. One to two eggs are laid, and hatch after an incubation period of between 48 and 51 days. When two eggs hatch, the elder chick always kills its younger sibling within a few days, so that only one chick is raised (2) (3) (5). Fledging occurs after 90 to 125 days, but the young crowned hawk-eagle is dependent on the parent birds for up to another 350 days, meaning the crowned hawk-eagle is usually only capable of breeding every other year (2) (3) (14).