|Genus:||Bubo (but see text)|
The spot-bellied eagle-owl (Bubo nipalensis), also known as the forest eagle-owl is a large bird of prey with a formidable appearance. It is a forest-inhabiting species found in the Indian Subcontinent and Southeast Asia.
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This, like its close relative, the barred eagle-owl, is one of the species that would have to be moved into Ketupa if that genus is to be retained, according to mtDNA cytochrome b sequence data (Olsen et al. 2002). Unlike the "fish owls" that were also considered to be included in Ketupa, the barred and the spot-bellied species are not closely tied to riparian habitats and piscivorous eating habits.
The spot-bellied eagle-owl is a large species of owl. It measures from 55 to 65 cm (22 to 26 in) long. A reported weight range of 1.3–1.4 kg (2.9–3.1 lb) is probably on the low end for the species, since those weights are roughly the same as those of the barred eagle-owl, which is considerably smaller going on total length, standard measurements and appearance. Other than size, the barred eagle-owl is similar in appearance to this species. Among standard measurements, this species typically measure 42.5 to 47 cm (16.7 to 18.5 in) in wing chord length, 23–25 cm (9.1–9.8 in) in tail length, 6–6.2 cm (2.4–2.4 in) in tarsal length and 5.2–5.4 cm (2.0–2.1 in) in culmen length. The subspecies of spot-bellied eagle-owl found on Sri Lanka, B. n. blighti, is considerably smaller than mainland birds in India, with a wing chord length of 37–41.2 cm (14.6–16.2 in) and a tail length of 18.4–21.5 cm (7.2–8.5 in).
The spot-bellied eagle-Owl is overall a brownish bird, with dark, coarse brown coloration over the back and upper wings. The throat and underparts are mainly pale fulvous in color with black and white horizontal stripes along the flanks of the body that become broad spots on the abdomen and undertail coverts. On the wings, the primaries are dark brown with lighter brown stripes and the secondaries are more heavily barred with buff-brown coloration. The lores are covered in bristly feathers and the cheeks are brownish-white with black feather shafts. The large ear tufts slant off to the sides.
This owl is noted for its strange, human-sounding call, it was suggested that it be the cryptid known as ulama or "Devil Bird" in Sri Lanka. A local name is Maha Bakamuna ("large horned owl"). According to http://www.cryptozoology.com, in July 2001 it was confirmed that ulama description perfectly matches spot-bellied eagle-owl. This call consists of a scream, which rises and then falls in tone. The territorial call of the species consists of low hoots, consistent with most eagle-owls, with two-second intervals between hoos.
Distribution and habitat
This species is distributed from the Lower Himalayas from Kumaon east to Burma, thence to central Laos and central Vietnam. They are found through India and peninsular Southeast Asia down into the southermost limits of the range in Sri Lanka and southern Thailand. The spot-bellied eagle-owl inhabits dense, evergreen forests or moist deciduous forests, though can range secondarily into tropical valleys, terrai and shola in the lower hills of India. It is mainly a species of tropical and subtropical foothills, mainly being distributed at elevations of 900–1,200 m (3,000–3,900 ft), though have been found at anywhere from sea-level to over 2,100 m (6,900 ft).
The spot-bellied eagle-Owl is nocturnal and often spends its day hidden in dense foliage of large forest trees. However, they have been observed on the move and even hunting during the day, especially in forests with minimal human disturbance. Their activity normally picks up at dusk as they begin to hunt.
This is a very powerful and bold predatory owl, which is assuredly at the top of the avian food chain in its range. They prey primarily upon gamebirds, including several species of pheasant. Among these, junglefowl are commonly eaten, as well as large peafowl. It also consumes an array of mammals, from small rodents to large prey such as jackals, hares, civets and even young muntjacs. They will also opportunistically prey upon snakes, lizards (including large monitor lizards) and fish. The spot-bellied eagle-owl pounces on birds while they're asleep on their perches in trees or bamboo clumps, often killing them in seconds with their powerful talons.
This species' nesting season is from December to March, however an egg has been recorded as late as June in Cachar. Most nesting sites are in large tree hollows. Alternately, they use abandoned stick nests made by other large birds, in many cases those previously built by eagles or kites. In this species, only one egg has ever been recorded per clutch and this is only one of two amongst all owl species (besides the buffy fish owl) where this is known to be the case. The egg is white and round ovoid shape with a smooth surface, averaging 61.2 mm × 49.9 mm (2.41 in × 1.96 in) in size. It has been reported that both sexes engage in incubation but this may not be the case (male owls generally do not incubate), with the male more likely temporarily covering the eggs while the female flies off for a short period. Few further details are known of their breeding biology, including the brooding and fledging stages due to this species reportedly being very fierce and aggressive in defense of their nests.
This species is generally uncommon, likely needing large hunting and breeding territories and thus occurs at low densities. However, it continues to occur over a large range and is not thought to be conservation dependent. Areas where deforestation occurs are likely to be vacated by this species, which is perhaps the only widespread threat faced by this owl.
- Olsen, Jery; Wink, Michael; Sauer-Gürth, Heidi & Trost, Susan (2002): A new Ninox owl from Sumba, Indonesia. Emu 102(3): 223-231. doi:10.1071/MU02006 PDF fulltext
- BirdLife International (2012). "Bubo nipalensis". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Claus König, Friedhelm Weick, Michael Wink. Owls of the World Yale University Press (2009), ISBN 0300142277
- Spot-bellied Eagle-Owl - Bubo nipalensis. Avis.indianbiodiversity.org. Retrieved on 2012-08-23.
- Glossary. Cryptozoology. Retrieved on 2012-08-23.
- Jetz, Walter; Sekercioglu, Cagan H.; Böhning-Gaese, Katrin (2008). "The Worldwide Variation in Avian Clutch Size across Species and Space". In Sheldon, Ben. PLoS Biology 6 (12): e303. doi:10.1371/journal.pbio.0060303.
- cryptozoology.com: Devil Bird. Retrieved 2006-DEC-23.