Family: Accipitridae
Genus: Nisaetus
Species: N. nanus
Subspecies: N. n. nanus, N. n. stresemanni

Wallace's Hawk Eagles are the world’s smallest hawk eagles. They live in southeast Asia, occupying lowland evergreen and semi-evergreen forest. They form a clade with Nisaetus alboniger (Blyth's Hawk Eagle), N. bartelsi (Javan Hawk Eagle), N. kelaarti (Legge's Hawk Eagle), and N. nipalensis (Mountain Hawk Eagle).

Physical Description:

Wallace's Hawk Eagles are black-brown from above and have a rufous-buff head with a black, buff-tipped crest. The throat is white with black malar and median stripes and the breast is cream-colored with black streaking. The belly is cream to buff and there is black-brown barring along the belly, flanks, and legs. The bases of the flight feathers and the wing coverts are buff with narrow black barring. The eyes and feet are yellow and the cere is black-gray.

Juveniles are almost identical to juvenile Nisaetus alboniger (Blyth’s Hawk Eagle), except for more buff along the head and a creamier underside. Eyes are gray to pale yellow and the cere is dull gray. Juveniles of the subspecies N. n. stresemanni are completely white along the head and underside and have a black crest.

Their call is a high-pitched "yik yee"; juveniles emit a breathy "yii yii yii yii" and "ee ee ee ee eeee". Listen to a Wallace's Hawk Eagle.

Size:

Length: 45-59 cm
Wingspan: 95-105 cm
Weight: 510-610 g

Habitat and Distribution:

They live in evergreen and semi-evergreen lowland forest. They have been found in logged and otherwise disturbed areas, but Wallace's Hawk Eagles do not occur in areas where there isn’t a high tree canopy. They are commonly recorded from 0-500 meters above sea level, rarely up to 1,000 m.

They inhabit a range that spans southeast Asia, in Myanmar, Thailand, the Malay Peninsula, Sumatra, and Borneo, from 11°N to 6°S. This almost completely overlaps the range of Nisaetus alboniger (Blyth's Hawk Eagle), except that Wallace's Hawk Eagles are restricted to lower elevations. Adults are sedentary though juveniles disperse from their breeding areas. There are an estimated 2,500-9,999 individuals over 1,110,000 km².

Diet and Hunting:

Birds, bats, frogs, skinks, and lizards have been recorded in their diet. They still-hunt from a perch.

Reproduction:

The breeding season is probably from November-February, since one recorded nest had a large chick in it during February. Pairs remain within their breeding territories year round.

The nest of a Wallace's Hawk Eagle is placed in the tree canopy and built out of sticks. It is lined with twigs, which are added continually until the young fledges. Clutch size is most likely one since more than one chick in a nest has never been recorded. Incubation and nesting periods are unknown.

Conservation:

Wallace's Hawk Eagles could be close to extinction in Thailand due to clearing of all lowland forest, and their global numbers have declined due to habitat destruction for logging and rubber and oil-palm plantations. They are currently listed as Vulnerable by BirdLife International.

Conservation measures proposed include surveys to determine their distribution compared to Nisaetus alboniger, researching their ecology, and giving the eagles legal protection in Myanmar, Thailand, Indonesia, and Malaysia.

Taxonomy:

Nisaetus nanus forms a clade with Nisaetus alboniger (Blyth's Hawk Eagle), N. bartelsi (Javan Hawk Eagle), N. kelaarti (Legge's Hawk Eagle), and N. nipalensis (Mountain Hawk Eagle).

Species in genus Nisaetus were formerly considered part of genus Spizaetus, but sequencing of one nuclear and two mitochondrial genes has shown that Asian hawk eagles (now Nisaetus) represent a different lineage than New World hawk eagles (Spizaetus). Therefore, Asian species in Spizaetus were moved to Nisaetus.

Subspecies:

There are two subspecies: N. n. nanus is found in Myanmar, Thailand, the Malay Peninsula, Borneo, and Sumatra, and N. n. stresemanni is found only in western Sumatra, on Nias Island.

Other Names:

Small Hawk Eagle, Orel malajský (Czech), Malajhøgeørn (Danish), Kleine Kuifarend (Dutch), Väike-tuttkotkas (Estonian), Pikkujalokotka (Finnish), Aigle de Wallace (French), Schungeladler (German), Elang Biliton, Elang Wallace (Indonesian), Aquilastore di Wallace (Italian), Uo-resukumataka (Japanese), Helang Selat (Malay), Dvergskogørn (Norwegian), Wojoynik maly (Polish), Águila-azor de Wallace (Spanish), Wallaces hökörn (Swedish).

Video of a Wallace's Hawk Eagle:

References:

http://www.arkive.org/wallaces-hawk-eagle/spizaetus-nanus/
http://avibase.bsc-eoc.org/species.jsp?avibaseid=42B300D28CA2552D
BirdLife International (2012) Species factsheet: Nisaetus nanus. Downloaded from http://www.birdlife.org on 14/04/2012.
Global Raptor Information Network. 2012. Species account: Wallace's Hawk-eagle Nisaetus nanus. Downloaded from http://www.globalraptors.org on 14 Apr. 2012
http://ibc.lynxeds.com/species/wallaces-hawk-eagle-spizaetus-nanus
http://www.planetofbirds.com/accipitriformes-accipitridae-wallaces-hawk-eagle-nisaetus-nanus
Ferguson-Lees, James, and Christie, David A. Raptors of the World. Houghton Mifflin Company, 2001.