Barn crow
| Barn crow | ||||||||||||
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Bluebird ( Corcorax melanorhamphos ) |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Corcorax | ||||||||||||
| Lesson , 1831 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Corcorax melanorhamphos | ||||||||||||
| ( Vieillot , 1817) |
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The throttle Crow ( Corcorax melanorhamphos ), sometimes called thrush pottery Crow or Australian Mountain Crow called, is occurring in Australia bird from the family of the mud nest crows (Corcoracidae).
features
Bluebirds reach a body length of 44 to 50 centimeters and a weight of 280 to 425 grams. There is no sexual dimorphism between the sexes in terms of plumage color . The plumage is a single color glossy black in both sexes. Only the underside of the hand wings is white, which can only be seen in flight. In English usage, the species is therefore referred to as White-winged Chough (white -winged crow ). The iris is red. The beak, which is slightly bent downwards, as well as the legs and feet are dark gray.
Distribution, subspecies and habitat
The throttling crow is found exclusively on the Australian continent. In addition to the in the east of Queensland until after New South Wales and northern Victoria occurring nominate Corcorax melanorhamphos melanorhamphos another is subspecies known:
- Corcorax melanorhamphos whiteae Mathews , 1912 - in South Australia
The main habitat of the species are open grass and arable areas as well as light eucalyptus forests.
Way of life
The birds feed on insects and seeds, and occasionally molluscs or small mammals. The food is usually looked for in groups on the ground. Hard mussel shells are beaten against stones with their beak and thus smashed. During a mouse plague, the birds were observed to kill the prey by hitting the ground and then devouring them. Fledglings take two years to learn the various feeding practices. The main breeding season falls from September to December, but can vary depending on the rainy season. Sometimes two broods are carried out per year. Barn crows live in pairs. They are supported by up to 18 family members from previous broods in building their nests and raising their young. The group builds the bowl-shaped nest together. It is made from mud at a height between 2.4 and 20 meters above the ground on a horizontal branch or in the fork of a branch, preferably on a eucalyptus tree ( eucalyptus ) and reinforced with grass. The individual layers of sludge are applied separately and new material is only added after a sufficient drying time. The construction time can extend over several months depending on the availability of the material. If there is not enough mud available, cow dung or emuco can also be used to build nests . After completion, it is usually provided with three to five eggs, which are hatched in 19 to 20 days. The nestling period is 24 to 30 days. The young only become independent after a further six to seven months, but then remain in the family group as helpers for later broods. In groups with a small number of helpers, the broods suffer considerable losses through starvation of the nestlings or even total loss. Groups with a small number of helpers sometimes kidnap young birds from neighboring family groups and enslave them.
Danger
Crustaceans are common, but not common, in their home areas. They are classified by the World Conservation Organization IUCN as 
" least concern = not at risk". Due to climatic drought, bush fires and the draining of areas for agriculture by humans, the extraction of the sludge required for nest building is limited in some areas. In return, the birds also settle on the outskirts of cities and parks.
Individual evidence
- ^ A b c d e Ian Rowley, Eleanor Russell: White-winged Chough (Corcorax melanorhamphos). In: Josep del Hoyo, Andrew Elliott, Jordi Sargatal, David A. Christie, Eduardo de Juana (eds.): Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona 2017 (accessed at http://www.hbw.com/node/60601 on May 3, 2017).
- ↑ dissemination
- ^ IOC World Bird List
- ↑ Birds in Backyards
- ↑ Kidnapping / enslavement
- ^ IUCN Red List
literature
- Josep del Hoyo , Andrew Elliott, Jordi Sargatal : Handbook of the Birds of the World. Volume 14: Bush-shrikes to Old World Sparrows. Lynx Edicions, Barcelona 2009, ISBN 978-84-96553-50-7 .
Web links
- Bluebird (Corcorax melanorhamphos) in the Encyclopedia of Life . Retrieved August 12, 2017.