Drum rail
| Drum rail | ||||||||||||
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Adult drum claws ( Habroptila wallacii ) |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Habroptila | ||||||||||||
| GR Gray , 1861 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Habroptila wallacii | ||||||||||||
| GR Gray , 1861 |
The drum rail ( Habroptila wallacii ) is a medium-sized flightless railing bird that occurs only on the Indonesian island of Halmahera , a northern Moluccan island , where it lives in inaccessible sago palm swamps near the forest. Its plumage is predominantly dark slate gray, while the skin around the eyes, beak, and legs are bright red. His call is a deep drumming sound accompanied by flapping wings. Since it is difficult to observe the shy bird in its densely vegetated environment, little is known about its behavior.
The drum rail, which was first described by the English biologist George Robert Gray in 1861, is the only species of the monotypical genus Habroptila . Their habitat is restricted, among other things, by the conversion of wetlands to rice-growing areas; the International Union for Conservation of Nature ( IUCN ) has classified them as endangered (Vulnerable, VU).
description
The drum rail is a strong, medium-sized, 35 to 40 cm long, flightless bird. In adult animals, the head, neck, coat, upper back and upper chest are dark slate gray, with the head and neck being the darkest in color. They are deep brown from the lower back to the tail. The back and rump , the shoulder feathers and the upper wing- coverts are of a washed-out olive-brown color, the color of the tail coverts and control feathers turns into a blackish brown. The upper wing coverts tend to be a washed-out slate gray on the outer edge, the large hand coverts are darker, deep brown, with a darker center. The coverts, the hand swing and the arm swing are very dark brown, the umbrella feathers are a bit lighter. The axillary feathers and the under wing coverts are dark slate-colored with brown feather centers. The lower breast up to the rump is dark slate gray, due to the dark brown feathers the area sometimes appears indistinctly banded. The under tail-coverts and the leg fletching are very dark brown to blackish.
The iris is red-orange, the bare skin around the eyes, the long, powerful beak, the forehead shield, and the legs and feet are bright red. There is a small wing claw. Males and females do not differ in appearance. The plumage of young birds has not been described.
distribution and habitat
The drum rail is endemic to Halmaheras , the largest island in the Indonesian archipelago of the Moluccas . Between 1950 and 2003 the drum rail was sighted from a protected area of West Halmahera Regency, which is at the beginning of the western peninsula, but before 1950 it was seen to the southernmost point of the island. Recent data show that it still lives in a much larger area, including the northeast of the island, and islanders claim it is also found in the swamps near Kao to the northwest.
The drum rail lives in dense, inaccessible, swampy thickets and swamp forest, especially sago palm swamps. It occurs in areas with mixed stands of screw trees and sago palms at sago / mangrove transitions, on swamp edges at the transition to foothills- deciduous forest and on alluvial land, preferably on peninsulas protruding into alluvial land. Reports of locally frequent occurrences in grasslands go back to confusion with the Rotsteiß-Kielralle ( Amaurornis moluccanus ).
The German ornithologist Gerd Heinrich , who was preparing for his research trip by rolling in nettles, described in the 1930s:
"I am solidly confident no European has ever seen this rail alive, for that requires such a degree of toughening and such demands on oneself as I cannot so easily attribute to others. Habroptila is shielded by the awful thorns of the sago swamps ... In this thorn wilderness, I walked barefoot and half-naked for weeks. "
“I am sure no European has seen this bird alive because it requires such a degree of hardening ... that I cannot easily admit to others. Habroptila is protected by the terrible thorns of the Sago swamps ... In this thorny wilderness I was barefoot and half-naked for weeks. "
Food and behavior
The food of the drum rail includes plant sprouts and insects. She takes sago from felled sago palms or looks for other food. She also swallows small stones to help break up the food. The birds are apparently monogamous , but little is known about their courtship behavior. The only known nest found in a rotting tree trunk in 2010 was covered with wood chips and dry leaves. The two young chicks were completely covered with black down feathers, as is typical for those who flee from the nest .
The bird's call is a deep drumming accompanied by a sound like tuk, tuk, tuk made with the wings. According to local legend, the sound is made when the bird hits a hollow tree trunk or branch with its feet. Gerd Heinrich pointed to the local name Soisa (drum) and described the call as a muted drumming purre - purre - purre - purre - purre , which sometimes ends in a loud shrill.
Hazard and protection
The distribution area of the drum rail is limited to the island of Halmahera , the population is estimated at 3,500 to 15,000 birds. The greatest threats to the species are the destruction of the sago swamps by commercial saga extraction , the creation of canals and the use of land for wet rice cultivation . In addition, flightless birds are endangered by imported predators. The drum rail is occasionally captured by dogs hunting deer and pigs.
The International Union for Conservation of Nature (IUCN) classifies the drum rail as vulnerable (VU) due to the small and likely further decreasing population size and the fragmentation of their habitat due to ongoing habitat loss .
Nothing is known about ongoing protective measures. A protected area of 3,550 km² was proposed for Halmahera between Lalobata and Ake Tajawe, which includes all types of landscape. It is unclear, however, whether suitable areas or areas of distribution for the drum rail are included.
literature
- Barry Taylor, Ber van Perlo: Rails . Pica / Christopher Helm, Robertsbridge, East Sussex 1998, ISBN 1-873403-59-3 . Pp. 451-452
Individual evidence
- ↑ a b c d e f Taylor, van Perlo (1998), pp. 451-452
- ↑ a b Invisible Rail Habroptila wallacii ( English ) In: Birdbase . Hokkaido Institute of Environmental Sciences. Retrieved June 17, 2011.
- ↑ a b Hanom Bashari, Bas van Balen: First breeding record of the Invisible Rail Habroptila wallacii . In: BirdingASIA . 15, 2011, pp. 20-22.
- ↑ a b c d Habroptila wallacii in the IUCN Red List of Threatened Species 2014.1. Listed by: BirdLife International, 2012. Retrieved June 24, 2014.
- ↑ Nigel J Collar: Pioneer of Asian ornithology: Gerd Heinrich . In: BirdingASIA . 11, 2009, pp. 33-40.
- ↑ Elizabeth A Krebs, David A Putland: Chic chicks: the evolution of chick ornamentation in rails . In: Behavioral Ecology . 15, No. 6, 2004, pp. 946-951. doi : 10.1093 / beheco / arh078 .
- ^ GAL de Haan: Notes on the Invisible Flightless Rail of Halmahera ( Habroptila wallacii Gray) . In: Amsterdam Naturalist . 1, 1950, pp. 57-60.
- ^ Heinrich, Gerd : Biological records of birds from Halmahera and Batjan . In: Journal of Ornithology . 97, No. 1, 1956, pp. 31-40. doi : 10.1007 / BF01670833 .
Web links
- Invisible Rail Habroptila wallacii Gray, GR, 1861 xeno-canto.org
- Invisible Rail Habroptila wallacii Oriental Bird Images
- Videos, photos and sound recordings about Invisible Rail (Habroptila wallacii) in the Internet Bird Collection
- Habroptila wallacii inthe IUCN Red List of Threatened Species 2014.1. Listed by: BirdLife International, 2012. Retrieved June 24, 2014.
- George Robert Gray: List of birds collected by Mr. Wallace at the Molucca Islands, with descriptions of new species . In: Proceedings of the Zoological Society of London . 28, 1860, p. 365. The first parameter must contain a numeric ID, namely the JSTOR ID from the "Article Stable URL". See template: JSTOR . .