Changeable Hawk-Eagle or Crested Hawk-Eagle is an Indian bird belonging to the family of eagle that bears a scientific name "Nisaetus cirrhatus" and is a bird of prey species of Accipitridae family. It was formerly placed in the genus Spizaetus, but studies pointed to the group being paraphyletic resulting in the Old World members being placed in Nisaetus and separated from the New World species. Changeable Hawk-Eagle concentrated in West Bengal, Sunderbans Forest Range.

Breeding Season of Changeable Hawk-Eagle
Changeable Hawk-Eagles breed in the Indian subcontinent, mainly in India and Sri Lanka, and from the southeast rim of the Himalayan Mountain Range across Southeast Asia to Indonesia and the Philippines. This is a bird occurring singly in open woodland, although island forms prefer a higher tree density. It builds a stick nest in a tree and lays a single egg.

Structure of Changeable Hawk-Eagle
Changeable Hawk-Eagle is a medium-large raptor at about 60-72 centimetres in length with a 127-138 centimetres wingspan, and a weight ranging from 1.2 to 1.9 kg. It is a relatively slender forest eagle with some subspecies being dimorphic giving the name "changeable". This and their complicated phylogeny further complicate precise identification. Normally Changeable hawk-eagle have the brown colour above, they have white below with barring on the undersides of the flight feathers and tail; black longitudinal streaks occur on the throat and chocolate streaks occur on the breast. Some subspecies have a crest of four feathers, but this is all but absent in others. The sexes are quite similar in their plumage, but males are about 15% smaller than females. The under parts and head of juveniles are whitish or buff with few dark streaks. The wings are long and parallel-sided, and are held flat in flight, which helps to distinguish this species from the similar mountain hawk-eagle. In overhead flight, comparatively rounded wings longish tail, white body and grey underside of wings are leading pointers.

Feedings of Changeable Hawk-Eagle
Changeable hawk-eagles eat mammals, birds, and reptiles. Changeable hawk-eagles keep a sharp lookout perched bolt upright on a bough amongst the canopy foliage of some high tree standing near a forest clearing. There, they wait for jungle fowl, pheasants, hares, and other small animals coming out into the open. The bird then swoops down forcefully, strikes, and bears the prey away in its talons.