Mountain Hawk-eagle

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Image:MtnHawkEagle.jpg

Common Name: Mountain Hawk-eagle
Scientific Name: Nisaetus nipalensis

Size: 27-33 inches (69-84 cm); Wingspan: 53-69 inches (134-175 cm)

Habitat: Asia; breeds in the Indian subcontinent, from India, Nepal to Thailand, Taiwan, Indonesia and Japan.

It breeds in heavily forested montane areas up to about 2,000 m, descending to lower elevations in winter. It inhabits subtropical and broad-leafed forests and fir forest at higher altitudes in Bhutan but avoids pine forests.

Status: Least Concern to Threatened. Global population: <10,000 Adult individuals with a decreasing population trend. The population is in decline owing to ongoing habitat destruction throughout its range. Though it is not considered a globally threatened species, the Japanese population is declining. As the species usually produces only one offspring, it was feared that the ongoing population reduction of N. n. orientalis might lead to loss of genetic diversity, and consequently inbreeding depression. However, genetic diversity was shown to be still considerable at present. The estimated Japanese subspecies population was <1,800 individuals in 2004.

Diet: Small mammals (especially hares) and terrestrial birds, including jungle fowl, domestic poultry, ducks, and pheasants, large snakes, and lizards. There are anecdotal accounts from several parts of its range of this eagle taking small monkeys as prey, but these may involve sick or dying animals.

Typically, these eagles still-hunt from a perch, stooping to take prey on the ground.

Nesting: Adults have brown upperparts and pale underparts, with barring on the undersides of the flight feathers and tail. The breast and belly and underwing coverts are heavily streaked. The wings are broad with a curved trailing edge, and are held in a shallow V in flight. Sexes are similar, but young birds are often whiter-headed. The Sri Lankan and south Indian population is smaller and has unstreaked buff underwing coverts.

Juveniles are pale in plumage coloration. They are particularly white from the chest to the abdomen. The iris varies greatly in color depending on the age. Their irises are ashy blue in fledglings, pale yellow at the age of 3, and almost yellow at the age of 4-5. Afterward, the yellow of the iris gradually deepens with age to become orange, hanging from orange to red and finally a deeper red.

They build a large stick nest placed in a tree, often growing in an isolated location. The nest size is 120cm by 100cm on average, and the thickness varies according to the age of use. They use thick dead branches for the frame and relatively thin branches for the upper structure. They lay twigs with green leaves in the inner cup. Eggs are laid from February to April. The clutch size is one egg and is white in color. It is about 57mm by 70mm in size.

The incubation period is about 43-50 days. Females mostly incubate eggs and nestlings, while males provide food. The nestling period is about 70-80 days and the young fledge from June to August. The fledging day is difficult to determine because the fledglings frequently return to the nest even after they left the nest and receive the food that the parent birds bring back. Cool Facts: They were earlier placed within the genus Spizaetus but molecular studies show that the Old World representatives were closer to the genus Ictinaetus than to the New World Spizaetus (in the stricter sense).

There are several subspecies:

  • N. n. orientalis is found in Japan. The Japanese subspecies is larger, lighter, and has only a very small crest, which is much larger in the other two subspecies
  • N. n. kelaarti, Legge’s Hawk-eagle. The Sri Lankan and south Indian population is smaller and has unstreaked buff underwing coverts. A 2008 study based on the geographic isolation and differences in call suggest that this be treated as a full species, Nisaetus kelaarti.
  • N. n. nipalensis is the nominate species.


This 3D model is found in Songbird ReMix Birds of Prey Volume IV: Eagles of the World

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