Turacos

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Turacos
Feather helmet turaco (Tauraco corythaix)

Feather helmet turaco ( Tauraco corythaix )

Systematics
Superclass : Jaw mouths (Gnathostomata)
Row : Land vertebrates (Tetrapoda)
Class : Birds (aves)
Order : Turacos
Family : Turacos
Scientific name of the  order
Musophagiformes
Seebohm , 1890
Scientific name of the  family
Musophagidae
Lesson , 1828

The turacos (Musophagidae) are a family of tropical, medium-sized, mostly very colorful birds. The family is the only one of the order Musophagiformes .

features

The colorful turacos reach a size of 36 to 75 centimeters. The giant turaco ( Corythaeola cristata ) is the largest species in the turaco family, measuring 70 to 75 centimeters. They have short, rounded wings in relation to the body, which are significantly shorter than the tail feathers. The relatively long tail is rounded at the end and is divided into ten stiff-shafted control feathers . Their beaks are short and strong. In some species, the beak is strongly compressed laterally, strongly rounded at the tip of the beak and quite high at the beak root. In some species the beak is serrated at the cutting edges; in other species the saw-like serration is not as pronounced.

In the case of the foot structure known as semi-zygodactyls , which differs from the foot structure of the cuckoo (Cuculidae), the outer toe can be rotated either into a forward or backward position. The second and third toes point forward. There are short staple membranes between the front toes. They can also be between the third and fourth (outer) toes, while the second toe, with its first limb, has for the most part grown together with the third toe. The first toe points backwards. When the birds are sitting on thick branches or on the ground, the turning toe is spread sideways. In the resting position, three toes point forward and one backward. When the turacos move in the branches of the trees, two toes point backwards and two forwards. Their clamp feet enable the turacos to climb perfectly in the trees.

Within their species, males and females do not differ in color or size. One exception is the white-bellied noise bird ( Corythaixoides leucogaster ), in which the male can be distinguished from the female's olive-green beak by its black beak. Many species have a feather bonnet on their head. Their plumage is mostly metallic green and blue with red to dark red wing feathers .

The presence of the two pigments turacin and turacoverdin is exceptional . Both dyes were named after the turacos, as they have not yet been found anywhere in the animal kingdom. The red, copper-containing dye turacine gives the wing feathers and, in some species, the feather bonnets their red to dark red color. The green fletching comes from the green dye turacoverdin . Other colors, such as blue, come about as in the case of watercolors by mixing the dyes. In rainy weather and when bathing, the dyes, which are soluble in the slightly alkaline water, are washed out in small quantities. In the genus of the noise birds ( Corythaixoides ), which have white to gray to brown plumage, these dyes are missing. The dyes are created from minerals in plant food, for example copper and iron compounds, which are converted in the body and passed on to the plumage.

Occurrence

Turacos inhabit the treetops in the forest and bush areas in tropical Africa south of the Sahara . The subspecies T. f is an exception . zanzibaricus , whose occurrence is limited to the island of Zanzibar . Species of the genus noise birds ( Corythaixoides ) inhabit open landscapes, such as tree and bush savannahs, wide open park landscapes and similar areas. Most of the representatives of the genus of the Helmturakos ( Tauraco ) have their habitat in the dense and wide primeval forests. However, the condition is the availability of water, since only there will enough fruits grow to form their nourishment. The giant turaco ( Corythaeola cristata ) prefers to inhabit clearings and gallery forests up to an altitude of 2000 to 2700 meters.

Way of life

nutrition

They feed mainly on vegetable food. Their diet includes berries, seeds, fruits, young shoots and insects. The seeds of the fruits are largely excreted undigested, so that the turacos play an important role in the spread. Among other things, they feed on the fruits of the tamarind tree ( Tamarindus indica ) and the mulberry fig ( Ficus sycomorus ). The birds do not do justice to the wrongly chosen name banana eater. In captivity, they also accept sliced ​​banana pieces, but turacos have never been observed to feed on bananas in the wild.

The habitats of the helmet turacos , giant turacos and shield turacos are located close to a body of water. The representatives of the genus noise birds have to cover a greater distance to get to a drinking place from the inhabited dry steppe areas. However, according to a report by Niethammer & Hoesch, you can do without water if necessary. When drinking, they dip the tip of the beak about two to three millimeters into the water. Like the pigeons (Columbidae), they suck up the water with three to four movements of their throats , lift their heads and close their bills.

Reproduction

Their breeding seasons depend on the distribution area. The shallow nests of loosely interwoven twigs with one to three eggs (usually two) are placed in the dense branches. Their nests are similar to the nests of pigeons. The eggs are white to greenish to bluish in color. Both adult birds incubate the eggs over a period of about three weeks. The adult birds also take turns feeding the young birds with the choked food. The offspring has a dense, gray to black downy dress. Just a few days after hatching, the young birds climb through the branches not far from the nest. After four weeks, the plumage of the young birds is fully grown. The offspring will fledge four to six weeks after hatching.

Systematics

Turacos were previously placed in the order of the cuckoo birds (Cuculiformes). Relationships with the mouse birds (Coliidae) were also assumed from Cabanis . Bonaparte took the view that they are related to the hornbills (Bucerotidae). According to the Sibley-Ahlquist taxonomy , they were placed in the "Musophagiformes" order. This classification has now been widely accepted and is supported by more recent phylogenetic studies. Among other things, they differ from the cuckoo birds in the number of cervical vertebrae.

The Turakos are divided into three subfamilies with a total of six genera and 23 species. The most species-rich genus are the helm turaco ( Tauraco ), while there is only one species of the genus Corythaeola , the giant turaco ( Corythaeola cristata ).

Giant turaco
( Corythaeola cristata )
White-eared turaco
( Tauraco leucotis )
Call of the white-eared turaco (Tauraco leucotis)

threat

Turacos are not particularly threatened as their populations are mostly stable and they live and breed far away from human settlements. A growing problem is the deforestation of trees in the forest areas. Due to the deforestation in the distribution area of ​​the Bannerman turaco ( Tauraco bannermani ), individual pieces of forest have emerged, which split the species into small populations. The distribution area of ​​the Bannerman turaco is becoming increasingly smaller and more fragmented. Since 2005 he is on the red list of the IUCN as endangered species ( endangered ). The Bannermann turaco has been listed in Appendix B of the Washington Convention on the Protection of Species (CITES) since June 1, 1997 and, as a strictly protected animal species, may no longer be imported into the European Union and traded within the EU in accordance with Appendix A of the EC Species Protection Ordinance .

swell

literature

  • Joseph Forshaw (Ed.): Encyclopedia of Birds. 1999, ISBN 3-8289-1557-4 .
  • Hans von Boetticher: Noisy birds, turacos and pisang eaters. 2004 (2nd, unchanged edition from 1955). ISBN 3-89432-607-7 .
  • Gottfried Mauersberger: Urania animal kingdom, birds. Urania-Verlag, 1991, ISBN 3-332-00491-3 .

Individual evidence

  1. ↑ Per GP Ericson et al .: Diversification of Neoaves: integration of molecular sequence data and fossils . Biol. Lett. doi : 10.1098 / rsbl.2006.0523 PDF
  2. ↑ Hackett et al .: A Phylogenomic Study of Birds Reveals Their Evolutionary History . Science, June 27, 2008. Vol. 320. No. 5884: 1763-1768 doi: 10.1126 / science.1157704 Abstract

Web links

Commons : Turakos (Musophagidae)  - Collection of images, videos and audio files