Goat milker (type)
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Goat milker ( Caprimulgus europaeus ) |
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| Linnaeus , 1758 |
The goat milker ( Caprimulgus europaeus ), also known as the European goat milker or nightjar , is the only member of the nightjar family (Caprimulgidae) to be found in Europe , alongside the red-necked goat milker ( Caprimulgus ruficollis ).
The well-sized, bark-colored, long-winged bird is crepuscular and nocturnal. The species spends the day sleeping, often sitting lengthways on a branch. It occurs from North Africa over large parts of Eurasia eastwards to the area of Lake Baikal . All populations are obligatory long-distance migrants with wintering areas in eastern and south-eastern Africa. Only a small proportion of the birds that breed in south-western Europe overwinter near the equator in western and central Africa.
Goat milkers feed on nocturnal swarming insects , mainly butterflies , which they catch in flight. They do not build a nest, but lay their mostly two eggs in a slight depression on bare ground.
In north-western and central Europe , the population declined since the end of the 19th century, a development that intensified significantly in the second half of the 20th century. Today the species has completely disappeared from many regions in Central Europe. However, the species is still well represented in south-west, south and south-east Europe. Globally, the species, of which six subspecies are described, is not considered endangered.
The peculiar name of the generic epithet caprimulgus comes from the erroneous view that the species would suckle on the udders of goats at night, which was spread by Pliny the Elder in his natural history. (Latin capra = goat; mulgere = to milk).
Appearance
The goat milker is an elongated, thrush-sized bird with a large, flat head and a very short, but very broad beak, which is surrounded by long bristles extending from the base of the beak. The short feet with the greatly elongated middle toe ( cleaning claw ) can hardly be seen in the field. The plumage is gray-brown, bark-colored, with lighter bands and black scribbling. The wings are unusually long, but quite narrow; In the last third of the underside of the wing, a distinctive white wing band appears , the outer control feathers of the long tail are also white, while the middle ones are dark black-brown. This white drawing is also present on the upper side of the wing, but less noticeable. Most of the time, a distinct white streak of beard and light plumage in the throat area can be seen. The females of almost the same size and weight are missing the white markings on the wings and tail as well as the light throat patch. In older females, the throat area is clearly lighter than the surrounding plumage, but tends to be cinnamon or reddish-brown in color and not whitish as in the males. The juvenile plumage is very similar to the female plumage, but overall lighter and less contrasting than the adult female. In flight, the bird looks significantly larger and hawk-like. The differences between the subspecies are not very clear and very difficult to determine using field ornithology.
measurements and weight
Depending on the subspecies, the total length of adult goat milkers (measured from the tip of the beak to the tip of the tail) is between 24 and 28 centimeters; the wingspan of 55 to 65 centimeters corresponds roughly to that of a male kestrel . The heaviest goat milkers weighed just over 100 grams, their average weight is between 68 and 85 grams. Individuals of the nominate form are on average the largest and also the heaviest.
voice
The species, which is territorial in the breeding area, is particularly noticeable because of its song. Mostly performed by an elevated singing station, it can best be compared with the sound of a small motorcycle driving by in a distance; it is performed for hours at dusk and at night, almost without a break. This varies in pitch and volume purring changes with greater excitement of quoorrooorrrorrr ... by erreeerreerrreerrreeerr ... This utterance can with the equally nightly Balzchören the natterjack be confused. If the call suddenly breaks off, one can sometimes hear very high, stretched kuuiik or guuiiek elements and repeated, quite loud clapping of the wings. At Nest is a dark, quiet from both parents wuuk - or quuuuk to hear -According that of professionals grunt is called. Short noises can also be heard especially during insect hunting and in excitement situations.
distribution
The distribution area of the species extends from the extreme northwest of Africa across southwestern Eurasia to the east, approximately to Lake Baikal . In Far Eastern Asia, the genus Caprimulgus is represented by the jungle nightjar ( C. indicus ), a species very closely related to the goat milker. Europe is almost completely populated, the species is also represented on most of the Mediterranean islands. It is only absent in Iceland, in the north of Scotland , in the north of Scandinavia and Russia, and in the southern part of the Peloponnese . In Central Europe it is a rare breeding bird with gaps, it is more common in Spain and in the Eastern European countries.
habitat
The goat milker lives in dry, warm, open landscapes with a sufficient supply of night-flying insects. In Europe, his preferred habitats are heaths and moors, he is also able to colonize light, sandy pine forests with large open spaces, clearcuts and windbreak areas. It also appears, especially in southern and southeastern Europe, on stony and sandy open areas of maquis , occasionally also in thinly overgrown dune sections. In Central Europe, secondary habitats such as military training areas or disused open-cast mining areas show the greatest population densities. In North Africa, the species breeds in stony terrain that is only sparsely covered with bushes. Closed forest areas are avoided by all subspecies, as are pure, largely vegetation-free deserts, only the subspecies C. e. plumpibes also breed in the peripheral areas of the Gobi . In general, the goat milker, as a heat-loving species, is more likely to inhabit the lowlands, but when food is cheap, it breeds into the subalpine area . In Asia, the species is regularly found at altitudes over 3000 meters, in the wintering areas even on the edge of the snow line at around 5000 meters.
If the basic requirements that the species places on the breeding site are met, the goat milker does not avoid human proximity. Outlying areas of small settlements even seem to be particularly attractive, probably because of the insects attracted by animal husbandry and light sources.
hikes
In its entire area of distribution, the goat milker is an obligatory migratory bird, which usually migrates individually (more rarely in small groups). The migration from the breeding areas begins as early as mid-July with the departure of the young birds. All goat milkers had cleared their summer quarters by October. Goat milkers are broad-fronted pullers and cross the Alps, the Mediterranean and the Sahara, or the inner-Asian steppe and desert areas without circumvention strategies. The main wintering area begins in South Sudan and extends to the Cape Province , whereby the most diverse biotopes and altitudes can be visited, provided that there is enough open space available for hunting. Goat milkers are also found in West Africa, starting in the southern Sahel region and going south to the Guinea coast , but in smaller numbers. The Asian subspecies also seem to prefer the wintering areas in East and Southeast Africa. There is also probably a small wintering area on the east coast of the Arabian Peninsula. Goat milkers are also regularly found in north-west India and north-east Pakistan during the winter months ; However, it is not clear whether these are hibernators. The first goat milkers do not arrive in the breeding area until mid-April, the majority only return home in the first and second May decade.
behavior
The goat milker is crepuscular and nocturnal all year round. Its activity phase begins shortly after sunset and ends at dawn. If there is enough food, a longer break and cleaning break is taken around the middle of the night. He spends the day resting on the ground, on tree stumps or on branches, always lengthways. In the breeding area, the same resting place is usually sought for weeks. In the event of a malfunction, goat milkers remain motionless for a long time. Only when the intruder has approached within a few meters does the bird suddenly flies up, but often settles down again after 20 to 40 meters. When it flies up, the alarm call and the clap of wings can often be heard. Goat milkers are not very sociable, they rarely move in small flocks and are usually found alone, even in winter quarters.
The goat milker's flight can be falcon-like fast, but it can also jump like a butterfly. Often he shakes. The cross-country flight is somewhat reminiscent of that of a cuckoo . On the ground he moves around, tripping, the body swaying a little back and forth.
Goat milkers like to sunbathe and take extensive dust baths.
Aggressive behavior
The males are very aggressive towards other conspecifics in the pairing and breeding phase. The territory owner flies towards the intruder, presenting the white plumage markings. Then he sits down and purrs a lot. That is usually enough to drive away the rival. Later this aggressiveness largely disappears and alien conspecifics are tolerated; they also often take part in brood care. The goat milker tries to drive away owls and occasionally bats by clapping their wings and flying attacks. Conversely , other birds also hate the goat milker. Potential nest robbers are attacked with hissing, hissing and air attacks. If this remains unsuccessful, he tries the intruder by Verleitestrategien fortzulocken from the nest. Brooding goat milkers only flee from a person when they have come within a few meters of their nest.
Hunting behavior
The prey is mostly in flight in rare stand hunting with short outage flights to the type of flycatchers captured, with diverse flight hunting methods to the falcon-like, raging hunting flight find the application range, gaukelnden search flight application. Only shortly before reaching the prey does the goat milker open its deeply split beak. The diagonally protruding bristles that surround the beak on the sides also contribute to the size and effectiveness of this fishing net. The goat milker seldom steals his insect prey on the ground.
Goat milkers not only hunt within their territories, but sometimes make long flights for food. Several individuals can be found at particularly abundant food sources.
food
The goat milker's diet consists of a wide variety of flying insects. Overall, butterflies (Lepidoptera) and beetles (Coleoptera) predominate , with butterflies and moths being preferred especially when rearing young . In addition, include Fly (Diptera), mayflies (Ephemeroptera), Hemiptera (Hemiptera) and Hymenoptera (Hymenoptera) for regular prey. Sand or fine gravel was often found in the stomachs of goat milkers that were examined, as well as remains of plants that may have been picked up by chance. The indigestible remains of the prey are regurgitated in relatively large spitting balls.
Breeding biology
Courtship and pairing
Goat milkers marry during the breeding season, and the same partners are mated again. They become sexually mature in the summer of the second year of life, but often do not breed until a year later. The male appears on average 10 days before the female in the breeding area and immediately occupies a territory that is vigorously defended, especially in the mating season. Females are mainly impressed by the song and the slow butterfly flights . During these flights the posture is almost vertical, the wings are raised in a V-shape and the white wing markings are clearly visible. The tail is fanned out, which also brings out the white tips of the outer control feathers. A clap of wings and the typical flight call can often be heard. The copulations usually take place near the nesting site on the ground.
Clutch, brood and nestling time
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The male shows the female potential breeding grounds in his territory. It does this by purring to the ground and purring cautiously for several seconds. The female comes along and purrs there too. Several such possible breeding sites are approached. The female later decides on one of these places as a breeding place. An optimal visual merging of the bird with its environment is decisive for the location of the breeding site. The European goat milker does not bring in any nesting material and does not change the breeding site. The clutch usually consists of two long-elliptical, light-colored eggs with dark spots averaging 31.5 × 22 millimeters in size. Three and four clutches were rarely found; possibly a second female is involved in such clutches. The eggs are almost exclusively incubated by the female for 18 days; the male only briefly detaches them at dusk and dawn.
The dune young hatch in a relatively advanced stage of development. They can follow the shadow just a few hours after hatching. In the first few days you will be huddled by the female. After about four days, both parents feed. When handing over the food, the youngster grips the beak of the parent bird, which passes a ball of insects while choking. A single feeding process can take up to 10 seconds. There are around 10 feedings per night, a bale of food can contain up to 150 individual insects. The young put their dung balls in the vicinity of the nesting site, so that the goat milker's feeding places often appear lined with white. Occasionally, both unmated males and females were observed as hatching helpers . At around 14 days, the boys begin their first flight exercises, at three weeks they can fly short distances. After about 5 weeks they are independent and migrate to the surrounding area before they move to the winter quarters.
The goat milkers of the northern populations only breed once a year, those of the southern areas regularly twice. Second broods are almost always box broods . The female lays a second clutch after the first clutch has incubated. The chicks of the first are cared for by the male, those of the second by the female. Occasionally there is also a change of partner between the broods.
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Systematics
Caprimulgus europaeus is a species of the genus Caprimulgus , in which, since the taxonomic revision in 2010, only 38 species whose breeding areas are in Eurasia and Africa are summarized. Six subspecies are described for the species, two of which (the nominate form C. e. Europaeus and C. e. Meridionalis ) occur in Europe. The differences in color, size and weight are clinical and in some cases are not very pronounced.
- Caprimulgus europaeus europaeus Linnaeus , 1758 : The nominate form breeds in Central and Western Europe as well as eastwards to Central Asia, approximately to the upper reaches of the Yenisei . It is the largest and darkest of the six subspecies. In the southwest of their breeding area there is a contact zone with C. e. meridionalis , in the southeast to C. e. sarudnyi .
- Caprimulgus europaeus meridionalis Hartert , 1896 : The distribution of this subspecies is south of the area inhabited by the nominate form. It begins in Spain and the Maghreb , encompasses southern Europe including most of the Mediterranean islands and extends over the Black Sea region to the Caucasus and the Caspian Sea . This subspecies is very similar to the nominate form, but is slightly smaller. The color of the upper side is more gray, the underside hardly shows any yellow tones. The white wing signs of the males are slightly larger than in the nominate form.
- Caprimulgus europaeus sarudnyi Hartert , 1912 : The main distribution area of this subspecies is in the northern Central Asian steppes, especially in Kazakhstan and Kyrgyzstan . The white wing marks of this species are very distinctive. The chest and abdomen are yellow-brown in color.
- Caprimulgus europaeus unwini Hume , 1871 : This strikingly light, almost gray subspecies breeds eastwards across Turkmenistan and Uzbekistan into the Tianshan . In terms of size, it is roughly between the nominate form and C. e. meridionalis .
- Caprimulgus europaeus plumipes Przewalski , 1876 : This subspecies is very similar to the one mentioned above. It can be distinguished from this by the warmer, more cinnamon-brown color of the top. The legs are feathered up to the toes. The breeding areas of this subspecies are in western Mongolia and northwestern China.
- Caprimulgus europaeus dementievi Stegmann , 1949 : Its distribution area extends furthest to the east and is located in the south-eastern Baikal area and in northeastern Mongolia. The basic color of the breast and abdominal plumage is clay yellow.
Inventory development
As with other flying insect hunters (e.g. red hawk , European roller or various shrike species ), the goat milking population has declined sharply in large parts of Europe since the middle of the last century. Habitat destruction and further intensified application of pesticides are primarily responsible for this in the breeding areas; But the increasing use of pesticides also seems to have an increasingly harmful effect in the wintering areas. In some regions, however, there has been a significant recovery of the population, especially in recent years, due to the use of secondary habitats. The Marienfließ nature reserve has around 70 goat milking areas. The type is classified as D ( declining ) throughout Europe . In the Red List of Germany's breeding birds from 2015, the species is listed in Category 3 as endangered. The goat milker also appears on the red lists in Switzerland, the Netherlands, the Czech Republic and Austria .
origin of the name
The name goes back to Pliny the Elder . He described the goat milker in his Naturalis historia (Liber X 26 Ivi 115). Allegedly, he sucked milk from goats at night, which would blind them or make them die. In reality, the goat milker is more likely to be attracted by the insects that accompany the grazing cattle, and the legend stems from a certain eeriness that surrounds the owl-like bird (see e.g. Brehms Tierleben, 2nd edition, 1882, 4th volume, p. 245).
Special customization
Like the sailors close to them, goat milkers can fall into a state of hypothermia if there is a prolonged lack of food , but this adaptation has not yet been adequately researched in wild individuals of C. europaeus . This energy-saving starvation sleep is always triggered by a lack of food and the associated weight loss. Some North American relatives (e.g. Poorwill, Phalaenoptilus nuttallii ) have developed this adaptation to such an extent that one can speak of a hibernation-like state.
literature
- David T. Holyoak & Martin Woodcock : Nightjars and their Allies . Oxford University Press 2001. pp 488-502. ISBN 0-19-854987-3
- Hans-Günther Bauer & Peter Berthold : The breeding birds of Central Europe. Existence and endangerment. 2nd revised edition; AULA, Wiesbaden 1997, ISBN 3-89104-613-8 , p. 268 f.
- Urs N. Glutz von Blotzheim (Hrsg.): Handbook of the birds of Central Europe . Edited by Kurt M. Bauer and Urs N. Glutz von Blotzheim, among others. Aula-Verlag, Wiesbaden. Volume 9. Columbiformes - Piciformes . 2nd, revised edition 1994 ISBN 3-89104-562-X , pp. 641-668.
- Reiner Schlegel: The goat milker (The new Brehm library, volume 406). Wittenberg Lutherstadt 1969
Web links
- BirdingGermany.de: goat milker
- British Society for the Protection of Birds: Milker (in English)
- Birds of Britain: Nightjar ( Memento from December 1, 2008 in the Internet Archive )
- Caprimulgus europaeus in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2004. Retrieved on January 2 of 2009.
- Videos, photos and sound recordings on Caprimulgus europaeus in the Internet Bird Collection
- Age and gender characteristics (PDF; 5.3 MB) by J. Blasco-Zumeta and G.-M. Heinze (Eng.)
- Nightjar feathers
Individual evidence
- ^ List of species of birds in Germany. (pdf) DO-G , accessed on January 2, 2020 .
- ↑ IUCN data sheet
- ^ James A. Jobling: Scientific Bird Names . Christopher Helm, London 2011. p. 90
- ↑ Voice example purring in xeno-canto
- ↑ Voice example xeno-canto: shouting and clapping wings
- ↑ Kin-Lan Han, Mark B. Robbins & Michael J. Braun: A multi-gene estimate of phylogeny in the nightjars and nighthawks (Caprimulgidae). Molecular Phylogenetics and Evolution, 55, 2, pp. 443-453, May 2010
- ↑ U. Steinhäuser: The NSG Marienfließ - the completely different landscape . Plauer Zeitung, Volume 120, No. 6, June 22, 2016
- ↑ Christoph Grüneberg, Hans-Günther Bauer, Heiko Haupt, Ommo Hüppop, Torsten Ryslavy, Peter Südbeck: Red List of Germany's Breeding Birds , 5 version . In: German Council for Bird Protection (Hrsg.): Reports on bird protection . tape 52 , November 30, 2015.
- ↑ Naturalis historia: Liber X 26 Ivi 115
