Monteiro-Toko
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Monteiro toko ( Tockus monteiri ), Spitzkoppe, Namibia |
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| Tockus monteiri | ||||||||||
| Hartlaub , 1865 |
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The Monteiro's Hornbill ( Tockus monteiri ) even Monteiro wrote, is a bird art that the hornbills belongs (Bucerotidae) and in the western sub-Saharan Africa occur. The distribution area is very small compared to other Toko species such as the gray Toko , no subspecies are described. Of all Toko species, it inhabits the habitat with the least rainfall.
Like all Tokos, the Monteiro Toko is also a cave breeder. The female sits for weeks in a nest hole, which she walled up except for a small gap. They and the nestlings that hatch after 24 to 27 days are cared for by the male who carries food to the brood cavity.
The stock situation of the Monteiro-Toko was classified in the IUCN Red List of Threatened Species in 2016 as “ Least Concern (LC) ” = “not endangered”. Because of its inhospitable habitat, there is little risk that habitat loss through anthropogenic deformation will lead to a decline of this species.
features
The Monteiro Toko is a medium-sized bird with a body length of 50 centimeters. The males have beaks with a length of 10.3 to 12.7 centimeters. The beak of the female is slightly smaller and measures between 8.6 and 10.5 centimeters. They weigh between 210 and 400 grams. The gender dimorphism is only slightly pronounced.
male
The males of the Monteiro toko are dark gray on the head, neck and front chest. The throat and the sides of the head are dashed in white. The back is brown, the upper tail-coverts are dark soot-brown. The middle two pairs of control springs are dark soot-brown, the rest of the 10 pairs of control springs have a dark soot-brown base, but are otherwise white. The underside of the body is whitish. The wrist wings are black with cream-colored tips. The outer wings are white with a black base, the inner wings are brown with paler edges. The elytra are brown with large cream-colored blotchy ends. The curved beak is red with a yellow base. The featherless orbital ring is black, the bare throat skin is dark gray. The eyes are brown, the legs and feet are black.
Females and young birds
The females correspond to that of the males with their body plumage. However, they are smaller, the beak is significantly shorter, the bare throat skin is blue-turquoise. the juveniles are similar to the adult birds, but have a smaller beak that is red-orange in color and gray at the base of the beak below the lower beak. The featherless parts of the face are pale flesh-colored, the eyes are brown and the legs are dark gray. The feathers, especially on the wing covers, have light brown tips.
voice
The calls are dark, harsh cackling sounds. Calls to announce the area sound kok-kok-kok-kokok-kokok-kokok .
Possible confusion
There are three types of Tokos in the distribution area, which can be confused with the Monteiro Toko.
The red-beaked toko is smaller and, like the southern yellow-beaked toko, has a stronger black and white body plumage. The Red Schnabeltoko also differs in its lighter head, while the Southern Yellow Schnabeltoko has a yellow beak. The voices of the two species are also higher.
The gray- toko has a gray-brown body plumage, the beak is black and white in the male and dark red and cream-colored in the female.
distribution and habitat
The Monteiro Toko lives in savannahs and dry thorn fields and only occurs in central and northwestern Namibia and southwestern Angola with around 400,000 individuals.
Of all hornbills , the Monteiro-Toko inhabits the regions with the least rainfall. It also occurs in regions with less than 100 millimeters of rain per year. The Monteiro-Toko prefers hill country with stony subsoil as a habitat. But it is also found in plains with sandy soils that are sparsely populated with individual thorn-reinforced trees. In Namibia, the average area of a pair of Monteiro tokos is 15 hectares. The breeding season begins with the beginning of the rainy season, but rainfall cannot be foreseen in the Monteiro-Toko area because it is not tied to any particular season. In the dry times, larger groups of Monteiro tokos regularly form, which move around in the distribution area in search of food.
food
The Monteiro Toko belongs within the genus of Tokos to the species that mainly find their food on the ground. On the ground, the Monteiro-Toko moves hopping and not walking, which could be an adaptation to the stony ground. They often dig for plant bulbs underground with their beak. They dig furrows that are 30 centimeters long and five centimeters long. The shrub vegetation is also searched for edible by the Monteiro-Toko. To rest, he either hangs up or sits on rocky cliffs.
In contrast to other representatives of the genus Tockus , which are omnivores, the Monteiro toko mainly feeds on insects and small arthropods . It also eats fruits, seeds, saplings, flowers and plant bulbs. The latter play a bigger role in its food spectrum, especially in dry seasons. The insects that the Monteiro toko eats include caterpillars, moths and various grasshoppers. It also breaks up wasp nests. Crickets of the genus Acanthoplus play an important role, especially during the breeding season, and make up 70 percent of the food that the male carries to the breeding cavity.
Reproduction
In Namibia, the breeding season usually falls between October and March. Egg-laying usually begins a month after heavy rains have set in.
The breeding season begins with the pairs beginning to inspect possible breeding holes. According to their habitat, in which trees are rare, Monteiro tokos mainly use crevices as breeding caves and, less often, tree caves. Typical places for suitable breeding caves are on rocky slopes along watercourses with a few trees nearby. The breeding caves can be at ground level, for example between tree roots, or 39 meters above the ground on a rocky slope.
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The visits to the breeding cave become more and more frequent, the female then gradually begins to seal crevices and cracks in the breeding cave from the outside. She mainly uses her own feces, leftover feed, but also occasionally clay. The nest cavity is padded with dry leaves, bits of cattle and blades of grass. Males do participate occasionally, but usually limit themselves to bringing material to the brood cavity. Couples occasionally use individual breeding caves for years.
The entire nesting cycle lasts 72 to 84 days, with incubation accounting for 24 to 27 days and the nestling period for 43 to 46 days. A female spends between five and eleven days in the breeding cave, which is then walled up by her except for a narrow gap, before she begins to lay eggs. During this time she also goes through the moult. It leaves the brood cavity around 19 to 25 days after the last nestling has hatched. The nestlings seal the nesting cavity again on their own, except for a narrow gap, after the female parent bird has left the nesting cavity. The female then takes part in feeding the young birds.
In Namibia the clutch size in the nests examined was usually 4.4 eggs. The clutch size depends on how much precipitation has fallen before. Young birds fledge from around 30 percent of the eggs they lay. The female lays the eggs two to three days apart. The nestlings hatch asynchronously according to this laying distance. It is usually the youngest nestlings who fail to fly out successfully because they are receiving too little food.
Trivia
The name Monteiro-Toko honors the Portuguese Joachim João Monteiro (1833–1878). Monteiro was a mining engineer, who at the same time collected specimens of the fauna and flora there during his stay in Angola from 1860 to 1875.
literature
- W. Grummt , H. Strehlow (Ed.): Zoo animal keeping birds. Verlag Harri Deutsch, Frankfurt am Main 2009, ISBN 978-3-8171-1636-2 .
- Alan Kemp: The Hornbills - Bucerotiformes. Oxford University Press, Oxford 1995, ISBN 0-19-857729-X .
Web links
- Tockus monteiri in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2012. Retrieved on October 2, 2016th
- Videos, photos and sound recordings of Tockus monteiri in the Internet Bird Collection
- Image at animaldiversity.ummz.umich.edu
- Species description in The Atlas of Southern African Birds .
Single receipts
- ↑ a b Tockus monteiri in the endangered Red List species the IUCN 2016 Posted by: BirdLife International, 2016. Retrieved on 9 October 2017th
- ↑ Species description in The Atlas of Southern African Birds . Retrieved October 3, 2016.
- ↑ a b c d Kemp: The Hornbills - Bucerotiformes. P. 129.
- ↑ Kemp: The Hornbills - Bucerotiformes. P. 128.
- ↑ a b c d Kemp: The Hornbills - Bucerotiformes. P. 130.
- ↑ Bo Beolens, Michael Watkins: Whose Bird? Men and Women Commemorated in the Common Names of Birds . Christopher Helm, London 2003, ISBN 0-7136-6647-1 , pp. 205 .