Andaman falcon owl
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Andaman falcon owl ( Ninox affinis ) |
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| Ninox affinis | ||||||||||
| Beavan , 1867 |
The Andaman falcon owl ( Ninox affinis ) belongs to the genus of the bush owls ( Ninox ). It is now known that it is only native to the Andamans , but not, as assumed in earlier works, also on the Nicobar Islands .
description
Dimensions
The approximately pigeon-sized Andaman falcon owl is very similar to the falcon owl ( Ninox scutulata ), but smaller at around 230 to 280 mm. Females are barely larger than males. The length of the wing from the bow (elbow joint) to the tip of the longest hand swing is 167 to 170 mm, the tail is 102 to 113 mm long. Weight information has not yet been published.
Appearance
The facial feathering is greyish, the iris is yellow. The 20 mm long bill, lined with white bristles, is yellowish to horn-colored (upper bill and tip somewhat paler) and the nasal wax skin is pale greenish.
The crown and mantle feathers are of a less intense gray-brown than those of the falcon owl, with hardly distinct, ocher-colored pinstripes. The gray feathering of the face hardly differs in color from the crown of the head, the coat feathers also have a reddish tint. It is also feathered in brown on the back, and the shoulder feathers are marked with a larger, pale, cinnamon to ocher-colored spot on the tip. Flight and tail feathers are banded brown and ocher and terminally clearly set off in brown, the arm wings are tinted red-brown.
The chest and belly are pale ocher brown to white and, apart from the flanks, are marked with light, chestnut to reddish brown, broad longitudinal stripes from the throat to the belly. The yellowish legs are feathered up to the bare or sparsely bristled 27 to 28 mm long toes . The claws are black to horn-colored.
Males and females do not differ in color. In the young birds the nestling down is less clearly striped on the chest and belly than in the adult bird.
Distinguishing features
The sympatric occurring Dunkelkauz ( Ninox obscura ) differs from the Andaman Falkenkauz in size and coloring. It is larger with 260 to 300 mm, the hand swing is 197 to 220 mm long, has no stripes on the underside and has a dark gray beak.
The allopatric falcon owl is overall somewhat paler and the vertex is striped. The longitudinal stripes on the chest and stomach stand out more clearly from the white and become wider on the flanks. The shoulder feathers are white-gray at the tip. The banding of the tail feathers is less pronounced. The beak is bluish to black.
voice
The call resembles a hollow, throaty, croaking tone falling at a pitch of 800 to 500 Hz, lasting about 450 ms at repeated intervals of several seconds, and sounds roughly like rough . It differs significantly from the soft, two-syllable, whistling call of the falcon owl, which sounds like a huuwup.
Distribution and habitat
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The Andaman falcon owl is endemic as a resident bird, mainly in lowland forests, mangroves and plantations of the Andaman Islands and has been observed when hunting in lower secondary forests .
behavior
Little is known about the behavior of the Andaman falcon owl. It is crepuscular and nocturnal , and rarely active during the day in cloudy weather. The couple spends the time of day huddled together in the shady branches of tall trees near the edge of the forest or in clearings, while the individual bird usually hides in the dense undergrowth, it is more shy than the dark owl. If there is a fault, it flies calmly to the next tree. Its flight pattern alternates between rapid wing flaps and gliding, it lands like a falcon and after a slight upward flight sits on a branch.
Nothing is known about reproduction so far.
nutrition
The Andaman hawk owl feeds mainly on insects and was often caught in the hunt for beetles and moths, such as. B. observed the owl butterfly Calyptra minuticornis , which occurs in the Indian-Southeast Asian region . Overall, however, little is known about diet.
Species protection
The Andaman falcon owl is classified as potentially endangered by the World Conservation Union (IUCN) and BirdLife International , as it is being pushed back in its habitat by growing populations, deforestation of primary forests and land use as cultivation and grazing land.
Taxonomy
The type specimen was discovered in Aberdeen Point, Port Blair , on South Andaman and first described by Captain Robert Cecil Beavan in the Ibis in 1867 under the title The Avifauna of the Andaman Islands .
The taxonomy of the monotypical Andaman falcon owl and its relationship with other bush owls has hardly been researched to this day. Further studies in ecology , behavior, voice and reproduction are also needed.
literature
- Sálim Ali, S. Dillon Ripley: Handbook of the Birds of India & Pakistan . tape 3 : Stone Curlews to Owls . Bombay 1969, p. 292-297 .
- Richard Grimmett et al .: Birds of the Indian subcontinent . Helm, London 1998, ISBN 0-7136-4004-9 , pp. 429-439 .
- Claus König , F. Weick : Owls of the world . 2nd Edition. Helm, London 2008, ISBN 978-0-7136-6548-2 , pp. 184-197, 448-473 .
- Penelope D. Olsen, JS Marks: Andaman Boobook (Ninox affinis) . In: Josep del Hoyo et al. (Ed.): Handbook of the Birds of the World Alive . Lynx, Barcelona 2017 ( online [accessed April 26, 2017]).