African throat pouch hornbills

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African throat pouch hornbills
Trumpeter hornbill, male

Trumpeter hornbill , male

Systematics
Sub-stem : Vertebrates (vertebrata)
Class : Birds (aves)
Order : Hornbills and hops (Bucerotiformes)
Family : Hornbills (Bucerotidae)
Genre : African throat pouch hornbills
Scientific name
Bycanistes
Cabanis & Heine , 1860
Hornbill
Silver-cheeked Hornbill, Kenya.
Gray-cheeked hornbill

African hornbills ( Bycanistes ), also known as trumpeter hornbills , are a genus of the hornbill family (Bucerotidae). They occur in sub-Saharan Africa.

Of the six extant species of valid trumpeter hornbill , the silvery-cheeked hornbill , the Gray-hornbill , the white-thighed hornbill and the hornbill as Least Concern (not endangered). The IUCN states that the brown-cheeked hornbird's population is endangered (vulnerable) .

features

The species belonging to the genus reach a body length between 45 and 70 centimeters. This makes them small to medium-sized hornbills. All species have a beak with a well-formed beak attachment, which in some species is reminiscent of the shape of an inverted chopping knife. This attachment ends with a pointed tip or abruptly in front of the tip of the beak.

The plumage is black and white. They all have in common that the back part of the back is white. The black upper plumage of most species usually has a metallic greenish shimmer. The feathers on the top of the head and on the neck are large and wide. They are often slightly splayed. The bare throat patch found in many hornbills is absent in these species.

Distribution area

All African throat hornbills occur south of the Sahara.

  • Trumpeter hornbill: occurs in Africa south of the equator and is absent only in West Africa. It inhabits forests on coasts and rivers up to medium mountain regions.
  • Gray-cheeked Hornbill: Tropical West and Central Africa. Inhabits evergreen coastal and mountain forests as well as other forest areas up to altitudes of 2600 meters.
  • Silver-cheeked hornbill: occurs in eastern tropical Africa. Inhabits coastal and mountain forests up to an altitude of 2600 meters.
  • Screaming hornbill: The smallest species among the African throat pouch hornbills occurs in tropical West and Central Africa. Inhabits evergreen forests and mangrove mountains, also occurs on plantations.
  • Brown-cheeked Hornbill: Tropical West Africa. Evergreen rainforests of the lowlands
  • Babali hornbill: Tropical West Africa, lives in evergreen rainforests of the lowlands.

Way of life

African hornbills are tree dwellers in the lowland and mountain rainforests. But they also colonize other forest areas and sometimes occur on plantations. They usually live in pairs, in small family groups. Occasionally, however, they also join larger groups and share sleeping spaces with them.

Like all hornbills, the African throat pouch hornbills are ominivorous. However, they mostly cover their nutritional needs with fruits. Figs play a major role in the diet of several species. The silver-cheeked hornbill is believed to play a major role in plant reproduction because it drops larger, non-digestible seeds about fifty meters from the fruiting tree. He swallows smaller seeds and excretes them with his excrement. Sticky mistletoe berries that stuck to the beak are stripped off the beak at its next resting place.

They also eat animal protein. Usually it is smaller vertebrates and arthropods that are eaten by them. But they also overwhelm larger vertebrates. The silver-cheeked hornbill has already been observed catching red-nosed green pigeons , an African species of fruit pigeon that reaches a body length of 30 centimeters and is therefore only slightly smaller than a city ​​pigeon . They show extremely aggressive behavior during the hunt. For example, they jump up and down on branches to scare off prey. Smaller troops of the silver cheeked hornbird also attack resting fruit bats together .

Reproduction

African throat-sac hornbills are among those species in which breeding helpers occasionally take part in reproduction. Like all hornbill species, the African throat-sac hornbills are cave-breeders. They breed in natural tree hollows, but sometimes also use rock hollows on steep slopes.

The female walls herself up in the brood cavity except for a narrow gap. What is unusual is the high degree of male participation. The trumpeter hornbill, the gray-cheeked hornbill and the silver-cheeked hornbill each swallow lumps of clay and choke them out again in the form of small balls of clay. The female then builds this clay when sealing the brood cavity. When a trumpeter hornbird's nesting cave was examined more closely, the material used weighed 1.47 kilograms. The clutches include one to three eggs. However, only one young bird usually grows. The nestlings hatch asynchronously, the younger nestling usually starves in the first days of life. The females usually stay in the nest hole until the offspring fly out.

During the breeding season, the male provides the female and the offspring with food, which he takes to the breeding cave. In nests of the gray-cheeked hornbill observed in Uganda, the male returned to the breeding cave every hour. He choked the food he had swallowed up at the nesting cave and gave it to the female. Over 200 pea-sized fruits or two to 17 olive-sized fruits were counted per visit. For gray-cheeked hornbills kept in captivity, what was eaten by the breeding pair during the breeding season and later by the breeding pair and the offspring was weighed. While before the breeding season the couple kept eating 560 grams of food a day, which consisted of 70 percent fruit and 30 percent animal protein, during the breeding season the proportion of animal protein doubled to 320 grams, while the fruit proportion remained constant at 420 grams. During the time that the nestlings were being fed, the hornbills ate 930 grams of fruit and 620 grams of animal protein.

species

The following species are counted among the African throat-sac hornbills:

literature

Web links

Commons : African throat pouch hornbills ( Bycanistes )  - Collection of images, videos and audio files

Single receipts

  1. ↑ Bycanistes bucinator in the Red List of Threatened Species of the IUCN 2016.10. Posted by: BirdLife International, 2016. Retrieved December 6, 2016.
  2. ↑ Bycanistes fistulator in the Red List of Threatened Species of the IUCN 2016.10. Posted by: BirdLife International, 2016. Retrieved December 10, 2016.
  3. ↑ Bycanistes brevis in the IUCN Red List of Threatened Species 2012.5. Listed by: BirdLife International, 2012. Retrieved December 6, 2016.
  4. ↑ Bycanistes subcylindricus in the IUCN Red List of Threatened Species 2016.10. Posted by: BirdLife International, 2016. Retrieved December 10, 2016.
  5. ↑ Bycanistes albotibialis in the endangered Red List species the IUCN 2016 Posted by: BirdLife International, 2016. Accessed December 8, 2016th
  6. ↑ Bycanistes cylindricus in the endangered Red List species the IUCN 2016 Posted by: BirdLife International, 2016. Retrieved on 7 December 2016th
  7. ↑ Kemp: The Hornbills - Bucerotiformes . P. 257.
  8. ↑ Gerhard Rösler: The wild pigeons of the earth - free life, keeping and breeding , Verlag M. & H. Schaper, Alfeld-Hannover 1996 ISBN 3-7944-0184-0 ., P. 258
  9. ↑ a b c Kemp: The Hornbills - Bucerotiformes . P. 259.
  10. ↑ Kemp: The Hornbills - Bucerotiformes . P. 248.
  11. ↑ Kemp: The Hornbills - Bucerotiformes . P. 256.