Changeable Hawk-Eagle

The changeable hawk-eagle (Nisaetus cirrhatus), also known as the crested hawk-eagle, is a medium-large bird of prey native to the forests of South Asia and Southeast Asia. It ranges from India and Sri Lanka through Southeast Asia to Indonesia and the Philippines. This species exhibits considerable variation in plumage, which gives it its name “changeable.” Adults typically measure between 60-72 cm (24-28 inches) in length, with a wingspan of approximately 127-138 cm (50-54 inches). Females are generally larger than males. The species is characterized by a prominent crest on its head, a long tail, and strong, yellow talons. Its plumage varies from dark brown to almost white, often with heavily streaked underparts. This variability can sometimes cause it to be mistaken for other raptors, such as the mountain hawk-eagle (Nisaetus nipalensis), but the changeable hawk-eagle is distinguished by its smaller size, less bulky build, longer tail and narrower wings.

The changeable hawk-eagle inhabits a variety of forested environments, including tropical and subtropical forests, deciduous woodlands, and even plantations. It prefers regions with dense canopy cover where it can perch and hunt. Its diet is diverse, consisting primarily of birds, mammals, and reptiles. Prey includes junglefowl, pheasants, small deer, monkeys, and large lizards. The eagle hunts from a perch, swooping down to capture its prey with its powerful talons. It may also hunt in flight, using its keen vision to spot and track potential prey.

This species is generally solitary or found in pairs. It is territorial, with pairs maintaining and defending large territories. The changeable hawk-eagle is known for its impressive aerial displays, particularly during the breeding season, when it performs elaborate flights and dives. Vocalizations include high-pitched whistles and screams, often heard during flight or when perched. These calls serve both to communicate with mates and to establish territory.

The breeding season of the changeable hawk-eagle varies geographically but generally occurs from November to April. The species constructs large stick nests high in the trees, often reusing the same nest year after year. Nests are typically lined with green leaves, which are replaced regularly.

The female lays a single egg, which she incubates for about 45-48 days. During this period, the male provides food for the female. After hatching, the chick remains in the nest for approximately 60-70 days before fledging. Both parents share the responsibility of feeding and protecting the chick until it becomes independent.

The changeable hawk-eagle is currently listed as least concern by the IUCN Red List, due to its wide distribution and large population. However, its population is declining due to habitat loss, hunting, and human disturbances. Deforestation for agriculture and urban development poses a significant threat to its natural habitats.