A monogamous species, Javan hawk-eagles remain with the same partner year after year, mating between January and June. Nesting in trees, just one egg is laid each year. The female incubates the egg for 47 days, during which time the male hunts to feed both himself and the female. After hatching, the female also hunts, providing the chick with meat for a relatively extended period. Even after fledging, the young bird will remain with its parents, living in their territory for more than a year. It will be three or four years before it forms a pair and breeds (4).
The Javan hawk-eagle hunts mainly from the branches of small trees, where it watches for small to medium-sized tree-dwelling mammals such as tree shrews, squirrels, fruit bats and occasionally young monkeys. It is also known to eat birds and reptiles when possible (5).