Stilts (genus)
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Yellow wagtail ( Motacilla flava ) |
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| Linnaeus , 1758 |
The stilts ( Motacilla ) are a songbird genus from the family of Wagtail . It comprises eleven - or, according to the most recent opinion, twelve - species and is mainly found in the Old World . Eight (or nine) species occur in Eurasia and North Africa , four in Sub-Saharan Africa . Only in the far west of Alaska were on the Bering Strait populations across the brook and the Yellow Wagtail in the New World foothold.
The oldest fossil finds of indeterminate stilt species come from the late Miocene in Hungary and the late Pliocene in Bulgaria .
features
Stilts are small to medium-sized songbirds with long to very long tails that are used to make constant rocking movements. The build is long and slender, the neck short and the head relatively small and round. The relatively thin and pointed beak shows a slight elevation above the featherless nostrils. The legs are long and slender, the feet quite long toe with more or less pronounced rear claws. The hand wing consists of 10 wings, of which the outer one is very small and narrow and is mostly hidden under the ninth, also quite small hand cover. The shield springs are greatly elongated and when the wings are folded they cover the wings to a large extent or even completely. The plumage of many species is very contrasting in color, especially in the splendid plumage, and then shows predominantly black, white, yellow or gray areas. The birds are usually less conspicuous in their winter and youthful plumage. The wing mostly shows clear light bands or fields, the umbrella feathers are noticeably brightly lined. The outside of the tail is conspicuously white, as the two or three outer control spring pairs have dark areas at most at the base.
Most species moult twice a year. The splendid plumage usually differs significantly from the resting plumage, only in the species with only one annual moult this feature is missing. The youth dress is easy to distinguish from all other clothes. The dress of the young birds in the first winter is mostly quite similar to the adult winter dress, but easy to address due to slight differences in the area of the wing.
Unlike the forest wagtail ( Dendronanthus indicus ), which switches to the adult dress already with youth Mauser, most stilts species moult the ages of 14 and 15 months in a Postnuptialmauser into adult dress. A sexual dimorphism is present in most species, but not very pronounced. In the youth and in the first winter dress, sex determination based on the plumage is usually not possible.
Stilts move continuously on the ground, only occasionally short jumps or catch flights are inserted. The head is moved back and forth in a nystagmatic manner , the tail makes up and down movements. The flight is undulating. Short, falling stretches with wings laid on are followed by fluttering upward movements.
Mamula wagtail
Gray wagtail
Lemon wagtail, resting dress
White wagtail of the subspecies M. a. personata
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voice
The singing is usually not very long and is often based on the typical calls. However, some species also show quite complex singing. The mostly short, simple calls are made in flight or from the ground. The repertoire is usually small, but the alarm calls differ significantly from the contact and flight calls.
Way of life and behavior
Stilts occur in numerous biotopes in open and semi-open landscapes from the plains to the high mountains. Many species are found preferentially in the vicinity of water, some are largely bound to inland waters. Several species are culture followers that show little fear of humans and also breed within settlements. Most of the time, stilts spend on the ground, but they often sit elevated to wait. During the breeding season they are often found singly or in pairs, most species are very territorial. In winter, however, swarms and sleeping communities often form, which in some species can include thousands of individuals.
Most of the stilts are migratory birds. While those of the temperate zones are medium to long-range migrants, the tropical species are short-range migrants or resident birds .
distribution
Except for small occurrences of the common wagtail and the yellow wagtail in the far west of Alaska, the occurrence of the genus is limited to the ancient world. Eight species inhabit Eurasia, four occur in Africa. Brook, sheep and gray wagtail are spread across the Palearctic, the occurrence of the latter species is divided into two large and several smaller sub-areas. The lemon wagtail inhabits large parts of West and Central Asia. The mamula wagtail occurs on the entire Indian subcontinent and the Japanese wagtail in Japan and possibly in parts of Korea . The Mekong wagtail, which was only described in 2001, is endemic in a very small area in northeast Cambodia and southern Laos . Widow, Cape and long-tailed wagtail colonize large parts of Sub-Saharan Africa , but the area of the latter is very patchy. The Madagascar wagtail occurs exclusively in Madagascar .
Systematics
The phylogenetic relationships between the species of the genus Motacilla as well as their number have long been controversial and still require further investigation today. In particular, the two forms of sheep and wagtail, which are common across the Palearctic, vary geographically and the phylogenetic relationships between the subspecies are very complex. For example, at times, some authors specifically identified the subspecies M. flava lutea , M. f. Feldegg and M. f. taivana and M. alba lugens and M. a. personata type status granted. On the other hand, the widow wagtail ( M. aguimp ) and the Japanese wagtail ( M. grandis ) were long regarded as subspecies of the white wagtail. There have also been numerous attempts species due to morphological comparisons to Super species or subgenera summarize or to spin off into separate species - such as sheep and Citrine in a genus Budytes that Cape Wagtail in Psomophilus that African Pied Wagtail in Aguimpa or mountain wagtail in Atolmodytes .
Recent molecular genetic studies lead to contradicting results. The results of the examinations of mitochondrial and nuclear DNA do not agree. This may be due, on the one hand, to the fact that the genus and species have only recently been split up, so that they have not yet been reflected in the mitochondrial DNA, and on the other hand, because hybridization falsifies the results. However, further analyzes of morphological and vocal characteristics suggest that the relationships are well represented by the nuclear DNA (simplified representation):
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For the white wagtail this means that the taxon is apparently monophyletic , although the internal systematics remains partly unclear. The black and white stilt species of Eurasia (brook, mamula, Japanese and Mekong wagtail) also apparently form a monophyletic group with the African widow wagtail. However, this contradicts the results with regard to the mitochondrial DNA, which suggest a more distant relationship between the widow wagtail and the other black and white species, but which brings the latter closer to the other Eurasian species.
Particular problems arise with the sheep and lemon wagtail. In the former, studies of both mitochondrial and nuclear DNA show a clear break between a western and an eastern group. The latter is apparently more closely related to the lemon wagtail than to the western wagtail. In the case of the lemon wagtail, however, further studies of the mitochondrial DNA suggest that the species is a paraphyletic taxon and that the two subspecies deserve species status, although studies of the nuclear DNA speak against it. Some authors such as the International Ornithologists' Union now recognize the eastern subspecies of the yellow wagtail Tschutschensis , macronyx and taivanensis as a separate species (Eastern yellow wagtail, Motacilla Tschutschensis ), others even grant all three species status. The IUCN has not followed this up to now.
Names
As a generic name, Linné used the old Latin name Motacilla , which can also be found in Varro and later in Conrad Gessner . The etymology of this word is unclear - especially since the obvious translation of the components with motus (= moving ) and cillere ( late Latin for moving quickly ) would be a pleonasm . So whether the name really - as a passage in Varro ( Motacilla quod semper movit caudam ) implies - refers to the movement of the tail and to this genus in general is not clearly verifiable.
It is also controversial whether the German name stilt can really be traced back to walking and long-legged wading in the water. Others use the Old High German name of the wagtail wagistarz (= wiggle tail ) as an explanation of the origin , which is said to have transformed into a water stilt over the centuries . This origin would also be the meaning of the name in other languages such as Low German Wippsteert , Engl. wagtail , Italian squassacoda or French hochequeue .
species
- Yellow wagtail ( Motacilla flava )
- Lemon wagtail ( Motacilla citreola )
- Capsule ( Motacilla capensis )
- Madagascar wagtail ( Motacilla flaviventris )
- Gray wagtail ( Motacilla cinerea )
- Long-tailed wagtail ( Motacilla clara )
- White wagtail ( Motacilla alba )
- Japanese wagtail ( Motacilla grandis )
- Mamula wagtail ( Motacilla maderaspatensis )
- Widow wagtail ( Motacilla aguimp )
- Mekong wagtail ( Motacilla samveasnae )
literature
- Per Alström, Krister Mild: Pipits and Wagtails of Europe, Asia and North America , Christopher Helm, London 2003, ISBN 0-7136-5834-7
- Urs N. Glutz von Blotzheim , Kurt M. Bauer: Handbook of the birds of Central Europe (HBV). Volume 10 / II, Passeriformes (1st part), Motacillidae - Prunellidae, AULA-Verlag, 1985/2001, ISBN 3-923527-00-4
- Anders Ödeen: Effects of post-glacial range expansions and populations of species richness , Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 664, Acta Universitatis Upsaliensis, Uppsala 2001
- Gary Voelker: Systematics and historical biogeography of wagtails: dispersal versus vicariance revisited , The Condor, 104 (4), pp. 725-739, 2002
- Alexandra Pavlova, Robert M. Zink, Sergei V. Drovetski, Yaroslav Red'kin, Sievert Rohwer: Phylogeographic patterns in Motacilla flava and Motacilla citreola: Species limits and population history , The Auk 120 (3), pp. 744-758, 2003
Web links
Individual evidence
- ↑ Alström / Mild, p. 480, s. literature
- ↑ For a detailed view and results regarding the mitochondrial DNA, see Alström / Mild (see literature) pp. 264 and 265
- ↑ Alström / Mild, p. 263f, s. literature
- ↑ Alström / Mild, p. 266 and Pavlova et al. (2003), p. literature
- ↑ a b Helmut Ölschlegel: The Wagtail , Die neue Brehm-Bücherei, A. Ziemsen Verlag, Wittenberg Lutherstadt 1985, ( ISBN 3-89432-359-0 , unchanged new edition from 2005), p. 6f
- ↑ Viktor Wember: The names of the birds in Europe - meaning of the German and scientific names , Aula Verlag, Wiebelsheim 2007, ISBN 3-89104-709-6