Two-tone gloss star
| Two-tone gloss star | ||||||||||||
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Two-colored gloss star ( Lamprotornis bicolor ) - Rietvlei Nature Reserve, Pretoria, South Africa |
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| Scientific name | ||||||||||||
| Lamprotornis bicolor | ||||||||||||
| ( Gmelin , 1789) |
The two-colored gloss star ( Lamprotornis bicolor ) is an endemic species of bird of the genus Actual gloss starlings ( Lamprotornis ), the family of starlings (Sturnidae) from the order of the passerine birds (Passeriformes) , which occurs in South Africa , including the kingdoms of Lesotho and Swaziland . Until a few years ago it belonged to the genus Spreo , which, however, based on genetic engineering analyzes, is now classified under the genus Lamprotornis. Its species is considered to be a medium-sized star that feeds primarily on animal protein such as insects, arthropods and small amphibians. Small fruits and seeds are also on his menu. It inhabits semi-arid open areas, grasslands to open areas on rivers and the sea.
features
Body and plumage
The two-colored gloss star is between 25 and 27 cm tall and weighs 93-113 grams, with the females being slightly smaller than the males. The plumage on the top is shiny in color. The two-color gloss star has so-called structure feathers, which produce their colors without pigments by refraction. The special shine is caused by the melanosomes embedded in the structure of the feathers in the melanocytes , which are under a keratin film . The special thing about its round melanosomes is that they are hollow inside. It has largely brown plumage with a partially oily green sheen. The lower abdomen and rump are whitish pinnate. The beak is black and from the lower jaw to below the eyes it has a yellow colored elongated narrow part with a black border. The legs and feet are black.
eyes
The iris of the eyes of the adult two-tone gloss star is white. Like most bird species, except for the nocturnal birds, the two-colored glossy 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 color perception in starlings (tetrachromatic vision). Three of the four cone-shaped receptor types are responsible for the area of light that is 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, the star is able to better and more easily recognize differences in other conspecifics, the degree of ripeness of the fruit or traces that we cannot see.
Vocalizations
He often gives a wiiek-wiiek in flight or when taking off and builds similar sounds into his melodies. When there is an alarm, he gives a sharp "skuoak".
Juvenile
The juveniles largely correspond to the adult two-colored glossy starlings, but their plumage is matt black and the area on the lower jaw is yellowish white. Only after 4–6 months does the sheen appear in their plumage and the colors become more intense. The irises of the eyes are brown and only after a year they slowly turn white from the outside to the inside and only reach adult status after about 2 years.
Habitat and Distribution
The two-colored gloss star is an endemic species found in southern Africa. Its range is approximately 788,000 km² and is located in South Africa including the kingdoms of Lesotho and Swaziland , although it is less common in Swaziland. Its discovery took place in the region of the Cape Peninsula, where it should no longer be found today. Its distribution in southern Africa is often shaped by local occurrences. It prefers open, semi-arid areas as well as grasslands, fields and pastures as well as sparsely populated areas or small towns, but also coastal regions with tidal areas are part of its habitat. He avoids cities with dense development or forests as well as desert-like areas. It can be found from sea level in some coastal regions up to 2,500 m in the Drakensberg. In Natal ( KwaZulu-Natal ) the two-color star can be found from 1200 m above sea level.
Way of life and behavior
The two-colored gloss star occurs regularly in smaller groups of 15-25 birds around the year. Often in these groups there are also the not yet adult young birds of the parents. Special territorial behavior is not known in this species. In their sleeping quarters they form flocks of up to 1000 birds, sometimes together with other bird species such as the lobster ( Creatophora cinerea ), weaver birds of the genus Ploceus or the red chalk falcon ( Falco naumanni ). What is striking is his particularly upright stance in contrast to most of the other true glossy stars and his strict, piercing look. The booted eagle ( Aquila pennatus ) and the peregrine falcon ( Falco peregrinus ) are considered to be its natural enemies.
It feeds mainly on the ground on various insects, such as ants , termites , various beetles , dragonflies , grasshoppers, as well as arthropods and small amphibians or ectoparasites from sheep and cows. He also sits on branches in trees to eat small fruits such as those of the fig species ( Ficus ), grapes and other berries, but also a wide variety of seeds such as those from the species of the logs ( Atriplex ), medlars ( Cotoneaster ) and others. Even nectar of aloe or agave among his food sources. The two-colored glossy starlings feed each other regularly, with the feeder standing in a very upright position and the recipient slightly crouching. Other starlings standing close by like to beg, but are then ignored. Usually it is the almost adult birds that feed the birds of the same age from the same breeding unit. There seems to be a dominance-controlled order among the group members, which is outwardly represented by the size of the white iris. Birds with a larger white iris are usually dominant over those with large, dark pupils and little white iris. This allows the conclusion that this is due to the different ages of the not yet adult birds.
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Reproduction
The two-colored starlings are considered monogamous and cooperative breeders, which often breed a second time a year 30 to 50 days after the first brood. You build your nests with approximately 1 m long tunnel-like entrances and an adjoining nest cavity. These can be crevices in rocks, walls or streets as well as sandy river banks or narrow pipes. The construction material of the nests consists of grass, muddy reeds, roots, wool, strips of paper, snake skin and other materials that appear suitable.
They lay between 2 and 6 oval, shiny, greenish-blue eggs, which can sometimes be reddish mottled. The breeding seasons are regionally very different and mostly dependent on the subsequent rainy seasons, which makes feeding the offspring easier. In some regions the breeding season is only a few months a year (Cape region), while in others it is incubated all year round. The main breeding seasons are between September and January, during which the female incubates the eggs for 14 to 16 days, as is the case with most common starlings. The subsequent rearing is carried out by both parents and up to 7 other brood helpers, who are usually composed of the not yet adult young birds of the previous brood or non-breeding adult two-colored starlings. The brood helpers bring food to up to 3 nests at the same time, mostly serving one nest. Occasionally they put the food a few meters in front of a nest. This leads to the conclusion that this feed is passed on by the members of the breeding community. The nestlings are born with bare skin, develop their plumage from the 6th day and are cared for in the nest for 23 to 27 days. After leaving the nest, the parents and helpers will continue to feed the young birds for at least 14 days.
The large honey indicator ( indicator indicator ) as well as the small honey indicator ( indicator minor ) as well as the jay cuckoo ( Clamator glandarius ) are known as breeding parasites of the two-colored glossy star .
Hazardous situation
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 two-tone star is therefore classified by the IUCN as safe (“least concern”).
Systematics
The two-colored gloss star is within the genus of the actual gloss star ( Lamprotornis ) in a related group with 6 other species. His sister species White Crest Starling ( Lamprotornis albicapillus ) and Fischer's Starling ( Lamprotornis fischeri ) formed last until the beginning of the 21st century its own genus Spreo . On the basis of mitochondrial and nuclear genetic engineering analyzes and the findings from them that are now considered to be reliable, these three species have been classified in the genus Lamprotornis . Nevertheless, some publications can still be found under the generic name Spreo bicolor.
The following clade represents part of the classification within the family tree of the actual glossy starlings.
| Lamprotornis |
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literature
- Charles Hilary Fry , Stuart Keith, Emil K. Urban (Eds.): The Birds of Africa. Volume 6: Picathartes to Oxpeckers. Christopher Helm, London 2000, ISBN 978-0-12-137306-1 , pp. 634-636.
- Frederike Woog See and be seen - the color vision of birds. In: Der Falke - Journal for Bird Watchers. 5/2009. ( Online ) Retrieved July 11, 2015.
- Rafael Maia, Dustin R. Rubenstein and Matthew D. Shawkey: Key ornamental innovations facilitate diversification in an avian Radiation. In: Biological Sciences - Evolution: PNAS. Volume 110, No. 26, 2013, 10687-10692; published ahead of print 10 June 2013, doi : 10.1073 / pnas.1220784110 . ( Full text ). Retrieved March 26, 2015.
- 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. Columbia University press article. Retrieved on March 22, 2015. ( online, PDF ( Memento from June 27, 2010 in the Internet Archive ))
- GE Hill, KJ McGraw (Ed.): Bird Coloration. Volume 1: Mechanisms and Measurements. Volume 2: Function and Evolution. 2006.
- 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, pp. 654-760.
Web links
- Videos, photos and sound recordings of African Pied Starling (Lamprotornis bicolor) in the Internet Bird Collection
Individual evidence
- ↑ a b c d e f g h i Charles Hilary Fry, Stuart Keith, Emil K. Urban (eds.): The Birds of Africa. Volume VI: Picathartes to Oxpeckers . Christopher Helm, London 2000, ISBN 978-0-12-137306-1 , pp. 634-636 .
- ↑ Rafael Maia, Dustin R. Rubenstein and Matthew D. Shawkey in: Key ornamental innovations facilitate diversification in an avian radiation ; Biological Sciences - Evolution: PNAS 2013 110 (26) 10687-10692. [1]
- ↑ Frederike Woog Seeing and being seen - color vision of birds in: Der Falke - Journal für Vogelbeobachter 5/2009. [2]
- ↑ a b C. Feare; A. Craig 1998: Starlings and Mynas . Christopher Helm, London. On Birdlife international.- factsheet, ( [3] ). Retrieved October 28, 2015.
- ↑ a b P.ARHockey, WRJ Dean, PGRyan (2005) Roberts - Birds of southern Africa (Lamprotornis bicolor) [4] . biodiversityexplorer.org, 2015. Retrieved October 29, 2015.
- ↑ Irby J. Lovette & Dustin R. Rubenstein 2007: A comprehensive molecular phylogeny of the Starlings ( Memento of November 17, 2015 in the Internet Archive ). Columbia.edu, 2015. Accessed March 22, 2015.