Green-tailed star
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Green-tailed gloss star (Lamprotornis chalybaeus chalybaeus) |
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| Lamprotornis chalybaeus | ||||||||||||
| Hemprich & Ehrenberg , 1828 |
The greater blue-eared starling ( Lamprotornis chalybaeus ) is south of the African Sahara occurring species of the genus Actual starlings ( Lamprotornis ), which is divided into four subspecies. It belongs to the family of starlings (Sturnidae) from the order of the passerine birds (Passeriformes) and with about 22.8 cm to the smaller starlings that prefer to stay in the open savannah with light trees. The adult glossy green-tailed star has a strongly iridescent , metallic, shiny, greenish-blue plumage and two rows of dark spots are visible on the wings. It feeds on a wide variety of fruits, seeds and insects.
features
Physique and plumage
The 21.5 - 24 cm long adult glossy green-tailed star weighs between 66 - 106 grams across all 4 subspecies. Females and males are about the same size. He has a highly iridescent, metallic shiny plumage. The plumage gets its play of colors from so-called structure feathers, which produce their colors only through light refraction and without pigments . 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 feature of these melanosomes are their platelet-like and hollow shape. The platelets are layered once and / or multiple times and are arranged in a uniform or alternating manner in their order.
The head, neck, neck and shoulders, as well as the back of the nominal form, have green shiny feathers with a slight bluish tinge. The rump is blue, with a slight purple touch on the lower chest that turns slightly purple towards the rump. The tail is relatively short but longer than that of the brass star ( Lamprotornis chloropterus ) and the tail feathers are bluish-green. Two rows of dark dots stand out on the laid-out wings. The legs and beak are black. In general, it should be noted that due to the different incidence of light, the colors of the plumage appear very different on the same bird due to the structure feathers.
eye
The irises of the eyes are yellowish, orange and sometimes red. Like most bird species, except for the nocturnal birds, the green-tailed 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 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 has a hoarse, croaking voice and makes a variety of sounds that can also be nasal or shrill. His alarm call sounds like a hard oath . (See links below)
Juvenile
About 6 weeks after hatching, the first plumage begins to form, which is mostly brown. The juvenile young birds look like the adult birds, but with little sheen and still a high proportion of brown rump and flanks. The sides of the head are also more brown. Only in the second year of life do they lose their first flight feathers during the moult and get their adult plumage. The iris of the eyes is brown and begins to change to a golden yellow color after 4–5 months. This process is not completed until the young age of around 14 months.
Habitat and Distribution
In some parts of its 7.83 million km² very large distribution area, the green-tailed star is a seasonally mobile and partially nomadic species. In its distribution area in sub-Saharan Africa, the occurrences are very regional and lie in a band above the Senegal in the west Continent to Sudan in the east and there further south to the northeast of South Africa . In the northern parts of the country of Guinea , Ivory Coast , Ghana , Togo and Benin it is considered a seasonally occurring non-breeding species. It is also considered non-breeding in the central parts of Nigeria and large parts of northern Cameroon . As a breeding species it is found in southern Mauritania , Senegal, Gambia , southern Mali , Burkina Faso , northern Nigeria , Niger , the northern tip of Cameroon, Chad , in the northern and eastern border area of southern Sudan , in the south of Sudan, Eritrea , Ethiopia , in the southeast Border area of the Democratic Republic of the Congo , Uganda , northern Rwanda , Burundi , Kenya , Tanzania , Zambia , Malawi , Mozambique , Zimbabwe , northern Botswana , southern Angola , northern Namibia and northeastern South Africa. It is the most widespread species of the actual glossy starlings ( Lamprotornis ), all of which only occur naturally on the African continent south of the Sahara.
Its habitat is the open savannah with tall trees and more densely vegetated ground, as well as scrubland and forests on larger rivers. It is preferably found in areas with mopane ( Colosphermum mopane ) and acacia trees. In Eritrea he could often be seen at the foot of hills. In Chad and Botswana it is mainly found along larger rivers and bodies of water with lush vegetation. It has also been observed in bog-like landscapes as well as in cultivated and inhabited areas, including cities.
Way of life and behavior
During the breeding season, the starling species classified as monogamous appears as a couple and shows territorial behavior during this time. Outside the breeding season, the glossy green-tailed star occurs both in smaller groups and in larger flocks of 300 or more birds, which then live together in a flexible social structure. So there are two different ways of living together. A smaller proportion occurs in family structures in which one or more pairs of parents live resident in an area together with some young birds throughout the year. In contrast, the vast majority only visit the ancestral regions during the breeding season and migrate to other areas for the rest of the year, as has been observed in Malawi and Kenya. Within this species there is a hierarchy in which the male specimens dominate the female among the adult green-tailed starlings. This behavior is already evident within the group of juveniles.
This starling species feeds mainly in a hopping gait on the ground, but also occasionally sitting in trees on fruits, such as various fig species (ficus) and Boscia senegalensis from the caper family (Capparaceae) and occasionally in the very dry regions also from Neem tree ( Azadirachta indica ). Similarly, the consumption of fruits from was Salvadora persica ( Salvadora persica ), Karandapflaume ( Carissa edulis ), Euclea divinorum an ebony greenhouse (Euclenacea), olive tree ( Olea europaea ) Aptodytes dimidiata from the family of Icacinaceae , Guibourtia coleosperma and Syzygium found and various seeds and the nectar of the agave sisalana from the asparagus family (Asparagaceae). Insects such as ants , termites , beetles or grasshoppers or small frogs and lizards , which they particularly like to peck after a fire, are also part of the diet. It has been observed that the green-tailed starlings move with herd animals and search the churned-up ground behind them for anything to eat. This is often done almost "industrially" by walking in a row next to each other and searching the ground. It was also observed as sheep, African buffalo ( Syncerus cafer ), wildebeest ( Connochaetes taurinus ) and Burchell's zebra ( Equus quagga ) exceedingly wary of ectoparasites liberated that as part of their diet program. They also use human waste near settlements. Puddles are used for drinking and swimming.
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In the event of an alarm, the green-tailed starlings flee and only after some time settle in trees. Then quite a while later they start again, just as if they had just taken a break on a long journey. Their flight style is direct and straightforward with short wing beats. They look for sleeping places in company with other conspecifics or together with other starling species such as the three-colored gloss star ( Lamprotornis superbus ) or lobed star ( Creatophora cinerea ) on trees or in the reeds. It has also often been observed that the birds rub off their wings, chest and feathered thighs briefly and quickly with ants such as the Anoplolepis custodiens . These are then either dropped or consumed. This behavior is often observed in various bird species and is supposed to help free from parasites with the help of the formic acid that is then secreted . Its natural enemies include the peregrine falcon ( Falco peregrinus )
Reproduction
The breeding season is very different from region to region. It extends in the northwest and central distribution areas from June to October through March to July in the northeast and from August to January in the east and south of Africa. The clutch usually consists of 2–5 smooth, blue or blue-green eggs, which are sometimes also red-brown or gray speckled and which are only incubated by the female. After about 14 days, the juveniles hatch and are fed first with insects and later also with berries. After about 23 days, the juveniles leave the nests. These are mainly at a height of 2 to 4 m, but can also be higher or lower depending on the region. The mostly cup-shaped nests are found in the wild in tree hollows of woodpeckers , bearded birds and abandoned nests of the Alektowebers ( Bubalornis albirostris ), in old rotten tree stumps or in other natural and artificial caverns and are covered with soft chaff, grass and feathers and occasionally with coarse Padded grass or snake skin. Regionally it happens that they do not build their nests in cavities, but put the nests in thorny bushes or use abandoned nests of the holy ibis ( Threskiornis aethiopicus ) and Abdim stork ( Ciconia abdimii ).
Danger
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 green-tailed star is therefore classified by the IUCN as 
(= least concern - not endangered).
Subspecies
Lamprotornis chalybaeus chalybaeus is the nominal form that is common in a wide band from Senegal in the west to Eastern Sudan in the east of the continent.
Lamprotornis chalybaeus cyaniventris ( Blyth , 1855): Its distribution area is in the countries of Eritrea, Somalia and Ethiopia in the northeast to western Kenya and eastern Uganda. Its plumage is more bluish on the head, neck, chest and top than the nominal shape. The torso is more blue-violet and the rump is more purple.
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Lamprotornis chalybaeus sycobius ( Hartlaub , 1859): Its distribution area extends from southwest Uganda, Burundi, southeast Kenya to the southeast of the Democratic Republic of the Congo, Tanzania and Mozambique. Its plumage on the head, neck and shoulders are greener, the trunk a little bluish
Lamprotornis chalybaeus nordmanni ( Hartert & Neumann , 1914): Its distribution area extends from southern Angola and northeastern Namibia to Botswana, southern Zambia to Zimbabwe and South Africa. It is similar to L. c. sycobius, however, with a slightly copper-colored tinge in the blue-purple.
Systematics
The green-tailed gloss star of the genus actual gloss starlings (Lamprotornis) is related to six other species, one of which is directly related. This is its sister species the Schillerglanzstar ( Lamprotornis iris )
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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 978-0-12-137306-1 , pp. 603-606.
- 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.
- PAR Hockey, WRJ Dean and PG Ryan 2005. Roberts - "Birds of southern Africa", VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town, Biodiversity explorer / iziko museums of Cape Town "The web of life in southern Africa ". ( online )
- Frederike Woog: Seeing and being seen - the color vision of birds. in: The falcon. - Journal for Bird Watchers 5/2009. ( Online ).
- 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; published ahead of print June 10, 2013, doi : 10.1073 / pnas.1220784110 .
- GE Hill & KJ McGraw (Eds, 2006): Bird Coloration. Vol. 1: Mechanisms and Measurements; Vol. 2: Function and Evolution .
- IJ Lovette, DR Rubenstein 2007: 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. 44, No. 3, pp. 1031-1056. Elsevier, September 2007, ( online ). doi: 10.1016 / j.ympev.2007.03.017 .
Web links
Videos, photos and sound recordings for Greater Blue-eared Glossy Starling (Lamprotornis chalybaeus) in the Internet Bird Collection
Detailed map of the distribution area on Avibase. [4]
xeno-canto: sound recordings - glossy green-tailed star ( Lamprotornis chalybaeus )
Individual evidence
- ↑ a b c d e f g h i j k l m n o C.H. Fry, S. Keith and EK Urban, (Eds) (2000). The birds of Africa Vol. VI: Picathartes to Oxpeckers. , Academic Press, London, 2000, ISBN 978-0-12-137306-1 , pp. 603-606.
- ↑ 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 BirdLife International (2015) Species factsheet: Lamprotornis chalybaeus. [3] . Retrieved November 8, 2015.
- ↑ a b A.JFK 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
- ^ A b PAR Hockey, WRJ Dean and PG Ryan 2005. Roberts - "Birds of southern Africa", VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town, Biodiversity explorer / iziko museums of Cape Town "The web of life in southern Africa ”. ( online ). Retrieved November 8, 2015
- ↑ Irby J. Lovette, Dustin R. Rubenstein 2007: A comprehensive molecular phylogeny of the Starlings. ( Memento of the original from November 17, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. on columbia.edu, 2015. Retrieved March 22, 2015.
