The Brown Hawk Owl is a dark brown, medium sized hawk-like owl with a round head and no ear-tufts. It is also known as the Oriental Hawk Owl or the Brown Boobook.
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Description: The facial disc is brown, with many narrow whitish radially orientated streaks. The eyes are bright yellow and have a narrow
dark area around them. The cere is dull green or greenish-brown, and the bill is bluish-black with a paler tip. There is a white spot on the forehead. Crown and
nape are chocolate-brown, indistinctly streaked ochre.
The back, mantle and wing-coverts are a uniform chocolate-brown. Primaries and secondaries are also chocolate-brown, inconspicuously barred ochre. The tail is rather long, and dark brown with a whitish tip, and is banded with broad, pale greyish-brown bars.
Underparts are whitish, with large drop-shaped rufous-brown streaks, becoming broad chevrons on the flanks.
Tarsi are feathered and toes are sparsely bristled or bare and coloured yellowish-green.
Size: Length 27-33cm. Wing length 145-233mm. Tail length Weight 170-230g. Considerable variation throughout its range. Males tend to be larger than females.
Habits: The Brown Hawk Owl is a Crepuscular and nocturnal bird. They will roost during the day, singly or in pairs, in the seclusion of a shady branch, often one thickly smothered with creepers. Will readily fly to another branch if disturbed. They are not normally active before dusk, but may sometimes move about during the daytime in cloudy weather. Sings from a branch high up in the top of a tree, usually the same location each night. Flight is with rapid wingbeats and glides.
Voice: A pleasant, almost musical song that is not loud, but carries far. There is some variation throughout its range, so it is possible
that the Brown Hawk Owl may actually be 3 or more distinct species.
Western variation: A hollow mellow double note lasting about 0.5 seconds with a rising inflection and emphasis on the second syllable - whoowup whoowup. The second note is a higher pitch and there is no audible gap between the two. This double note is uttered at intervals of about 0.6 to 0.9 seconds in runs of 6 to 20 couplets.
Northern variation: Two or Three short, mellow, hollow woop notes at the same pitch with an audible gap between the notes. These couplets, or triplets, are uttered in a series with pauses of 0.3 to 0.9 seconds between them. Other vocalisations described include a sharp, nasal, shrill heeoo, a quiet rolling, protracted kerrrr similar to a cat purring, and a cat-like meew.
Eastern (Philippines) variation: Similar to Northern variation, but notes are lower-pitched with a shorter pause between them.
Hunting & Food: The Brown Hawk Owl feeds mainly on large insects such as beetles and grasshoppers, but also frogs, lizards, small birds, mice and occasionally small insectivorous bats or crabs. They hunt at dusk using a perch on a tree stump or post to look for prey. They have been observed jumping up to take a passing insects in the claws, and hawking insects in the air like a nightjar.
Breeding: Breeding season is the end of May-June in Japan, May-July in north India, and March-April in Sumatra. The Brown Hawk Owl is very
vocal during the breeding season, and can sing almost continuously for hours, especially on moonlit nights. Male and female will join in irregular duets, or
several distant birds will answer one another from different directions, sometimes resulting in choruses with birds in neighbouring territories.
Nests are 5-20m above the ground in large irregular holes or hollow trees, with the hole being around 30-80cm deep and having a diameter of 20-30cm. Nest holes are often used in successive years by the same pair. They are also reported to nest on the ground in woodpiles and rockeries, and in nestboxes.
Eggs are laid in a layer of natural debris at the bottom of the hole. Northern races lay 2-5 eggs within 5-7 days, while southern races usually lay only 2 eggs. Eggs are white, roundish and average 36x31mm.
The female alone incubates the eggs, while the male provides her with food. Incubation lasts 25 or more days, and starts with the third egg, suggesting synchronous hatching within the last 2 days of the incubation period. Despite this, there are conspicuous size differences among the brood of chicks. Fledglings leave the nest hole 24-27 days after hatching, and are fed by both parents.
Habitat: In northern regions, inhabits forest and woodland up to 1700m elevation.
In Japan, this owl occurs particularly in broadleaved deciduous and broadleaved evergreen woodland, mixed with conifer plantations, and tends to frequent forest edges. Brown Hawk Owls are also associated with human habitations and may even breed in urban areas that contain well-wooded areas with tall trees.
In the west of its range, they are found in forest, well-wooded country and groves of trees, particularly around water and bordering forest streams or watercourses, and often close to human habitation.
In southeast Asia, occurs exclusively in primary lowland rainforest, far from human habitation.
Distribution: Indian subcontinent to east Siberia and Japan, south to the Andamans, Malay Peninsula, Great and Lesser Sundas, Sulawesi, Moluccas, Taiwan and Philippines.
Status: Northern populations fairly common, southern populations more at risk.
Original Description: Raffles, T. Stamford. 1822. Transactions of the Linnean Society of London (Trans. Linn. Soc. London) (1) 13: p. 280.