Gigantic star
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Giant glossy star ( Lamprotornis australis ) on its observation seat |
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| Lamprotornis australis | ||||||||||||
| ( A. Smith , 1836) |
The giant gloss star ( Lamprotornis australis ) from the genus of the actual gloss starlings ( Lamprotornis ) is a species of bird from the family of starlings (Sturnidae) and belongs to the order of the passerine birds (Passeriformes). It has a strongly metallic, shimmering, iridescent plumage in blue to purple hues and is considered a monogamous bird. Its distribution area is in the southern African states with open, lightly forested areas and savannas with trees and clear soil. It feeds mainly on various insects and fruits.
features
Physique and plumage
The giant gloss star measures around 30–34 cm. Its weight is between 74 and 138 grams. In Zambia, this species of starling stands out as a relatively lightweight in the lower weight range, while in Namibia it has the significantly higher weights.
The plumage on the upper side has uniformly strong iridescent metallic shimmering colors. Its plumage consists of so-called structural feathers, which evoke their colors by refraction of light without pigments. The special shine is caused by the melanosomes embedded in the structure of the feathers , which are under a keratin film . The special feature of these melanosomes are their platelet-like and hollow shape. The platelets are simple, multilayered or arranged alternately (alternately).
The head shows itself in an iridescent greenish blue, which is clearly delimited in the transition to the neck. The nape and throat appear a purple blue with a slight purple tinge. The reins between the beak and the eye are black and the ear covers and the spots below the eyes are dark bronze. The chin and throat are blue-green, shoulders and back shimmer metallic blue-green and merge into a slightly purple sheen on the rump and tail. The chest and stomach area are also blue-green, while the center of the belt area is often purple. The sides, lower abdomen and lower tail feathers are blue. The first two wing feathers appear in a dark blue with a purple sheen and the following wing feathers in a shaded, strong blue. The wings are wide and rounded at the ends. The beak and legs are black.
The characteristics of juveniles differ significantly from adult birds. They lack the sheen of the adult giant starlings and they look unattractive and matt. The back area shows a greenish blue and the underside is matt in a bluish black.
eye
The eyes of the giant gloss star are dark brown. Like most birds, apart from the nocturnal species, the magnificent starlings see their environment differently than we humans. In contrast to humans, the star has four and not just three types of photoreceptors (also called photoreceptors ) on the retina for color vision . In addition to the thinner rod-shaped receptors responsible for black and white vision, four cone-shaped receptor types are responsible for perception in starlings (tetrachromatic vision). Three of the four cone-shaped receptor types are responsible for the area of light that is also visible to humans (trichromatic vision), which make the three primary colors red, green and blue visible. The fourth receptor is responsible for the perception in the area of ultraviolet light , which is not visible to humans. The incidence of light stimulates the various types of receptors within the strongly folded membranes, which are provided with different colored oil droplets, with different intensities. The responsible receptors react more or less strongly to the different wavelengths of light, so that the different colors and hues are perceived. The additional UV receptor compared to humans allows starlings to perceive our environment in a much more differentiated or different way. With the help of the UV receptors, they are able to better and more easily recognize differences in their fellow species, the degree of ripeness of the fruit or UV-reflecting traces that we cannot see.
Vocalizations
The sounds of the giant glossy star are a mixture of rolling, whispering and high-pitched, creaking and creaking tones as well as muffled sounds. His chants are often of a longer nature with several short pauses. The sounds are swarmed in a deafening scream.
Habitat and Distribution
He prefers open forest areas and savannahs with various types of acacia (Acacieae) such as the camel thorn acacia ( Vachellia erioloba ) (syn .: Acacia erioloba ) and Senegalia nigrescens (syn .: Acacia nigrescens ) and mopane trees a carob family (Caesalpinioideae). However, it could not be found in areas with the Brachystegia carob family . Its habitats are regularly from the lowlands up to 1500 m above sea level.
Its distribution area of around 1.5 million km² is predominantly in the south-west and center of southern Africa, from south-east Angola to south-west Zambia , further south of it in central Namibia across east Namibia , along the Zambezi to east Botswana and the outermost tip of Zimbabwe in the four country corner and the western border area. The southern habitat is formed by the Kalahari Gemsbok National Park and the South African Kgalagadi Transfrontier National Park down to the lower north-west province (formerly the West Transvaal ). An isolated occurrence is located in the Kruger National Park, which extends in the northeastern provinces of South Africa, Limpopo and Mpumalanga , as far as just beyond the border to Mozambique and the lower-lying eastern Swaziland.
Way of life and behavior
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The giant gloss star prefers free grassed ground with trees and lives there mostly in small groups. It usually flies together with up to 50 conspecifics or often other species of the starlings. The distribution of the groups is consistently patchy, so that the different groups usually do not meet. A specialty are swarms of up to 1000 specimens in winter in Botswana. The giant starlings often sing for long periods of time when they sleep and sit in groups singing on the lower branches of a tree. With their head back and their beak up, they let their wings hang down. You often also sing on the floor. The moult takes place before the breeding season.
They usually walk across the floor in large steps to eat. Their preferred food is arthropods such as grasshoppers, termites, ants and beetles. When it comes to fruits, your preferred diet is berries and other similar fresh fruits such as Diospyros mespiliformis from the ebony family. The flowers of acacia species are also on the menu. In the vicinity of camps, they often become scavengers by consuming kitchen garbage, among other things.
Reproduction
The giant starlings live monogamous. They usually build their nests in natural tree hollows or holes made by woodpeckers (Picidae) and African bearded birds (Lybiidae), which must be relatively large for this species of bird. The tree hollows are regularly between 2 and 7 m high. They also use crevices in the rock that appear suitable, as well as holes in buildings, nesting boxes or the like. The nests are mostly padded with fresh green grass, green leaves, feathers, snake skins, but also fabric, paper or plastic strips. Mostly they lay 2 to 4 blue to green-blue smooth and shiny eggs, which are sometimes provided with red-brown spots, usually at the thicker end of the eggs. The eggs are on average 29 × 20 mm in size and weigh 7 to 9 grams. In Namibia and Botswana the breeding season is between January and April, in Zambia mainly in March and in South Africa mainly from October to January. The incubation period is around 15 days and the nestlings can be raised further for 20–24 days. During this time, both parents take care of the juveniles and do not use any helpers for the brood, as is sometimes the case with other types of starlings. The Common Blue Cuckoo ( Clamator glandarius ) is a breeding parasite . Its young birds, however, are towered over by their own brood of the giant starlings, which gives them significant advantages when it comes to feeding.
Hazardous situation
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There is no reliable information on the size of the world population, but the species is considered common in most of its range and the population as stable. The IUCN therefore classifies the giant gloss star as safe (“least concern”).
Systematics
The Riesenglanzstar stands within the genus of the actual glossy starlings ( Lamprotornis ) in a related group with four other species, all of which have very long and finely banded tails. It forms the basic species for this group.
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literature
- Charles Hilary Fry , Stuart Keith , Emil K. Urban (Eds.): The Birds of Africa. Volume VI: Picathartes to Oxpeckers. Christopher Helm, London 2000, ISBN 0-12-137306-1 , pp. 618-619.
- AJFK Craig, CJ Feare: Family Sturnidae (Starlings). In: J. del Hoyo, A. Elliot, DA Christie (Eds.): 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 .
- Rafael Maia, Dustin R. Rubenstein, Matthew D. Shawkey: Key ornamental innovations facilitate diversification in an avian radiation. In: Biological Sciences - Evolution: PNAS. 110 (26), 2013, pp. 10687-10692; published ahead of print June 10, 2013, doi: 10.1073 / pnas.1220784110 .
- GE Hill, KJ McGraw (Ed.): Bird Coloration. Vol. 1: Mechanisms and Measurements. 2006, ISBN 0-674-01893-1 ; Vol. 2: Function and Evolution. 2006, ISBN 0-674-02176-2 .
- IJ Lovette, DR Rubenstein: A comprehensive molecular phylogeny of the starlings (Aves: Sturnidae) and mockingbirds (Aves: Mimidae): Congruent mtDNA and nuclear trees for a cosmopolitan avian radiation. In: Molecular Phylogenetics and Evolution. Volume 44, No. 3, September 2007, pp. 1031-1056. doi: 10.1016 / j.ympev.2007.03.017 . ( online PDF ( memento of June 27, 2010 in the Internet Archive ), accessed on March 22, 2015.)
- PAR Hockey, WRJ Dean, PG Ryan: Roberts Birds of southern Africa. 7th edition. John Voelcker Bird Book Fund, Cape Town 2005, ISBN 0-620-34053-3 . (biodiversityexplorer.org iziko museums of Cape Town “The web of life in southern Africa”. Accessed August 15, 2015)
Web links
- Knobthorn ( Senegalia nigrescens ), English. Senegalia nigrescens
Individual evidence
- ↑ a b c d e f g h CH Fry, S. Keith, EK Urban: The birds of Africa. Volume VI, Academic Press, London 2000, pp. 618-619.
- ↑ Rafael Maia, Dustin R. Rubenstein, Matthew D. Shawkey: Key ornamental innovations facilitate diversification in an avian radiation . In: Proceedings of the National Academy of Sciences . tape 110 , no. 26 , June 25, 2013, ISSN 0027-8424 , p. 10687-10692 , doi : 10.1073 / pnas.1220784110 ( pnas.org ).
- ↑ Frederike Woog: See and be seen - color vision of birds. In: The falcon. Journal for bird watchers. No. 5, 2009. (schattenblick.de)
- ↑ a b Lamprotornis australis. In: Roberts Birds of southern Africa. 2015. (biodiversityexplorer.org , accessed August 15, 2015)
- ↑ Lamprotornis australis. In: BirdLife International (2015) Species factsheet. (birdlife.org , accessed August 14, 2015)
- ↑ ( Redlist. Version 2015.2 ). Retrieved August 15, 2015.
- ↑ Irby J. Lovette, Dustin R. Rubenstein: A comprehensive molecular phylogeny of the Starlings. 2007 ( www.columbia.edu ( Memento from November 17, 2015 in the Internet Archive ), accessed on March 22, 2015)