Marsh harrier
| Marsh harrier | ||||||||||||
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Marsh harrier ( Circus aeruginosus ) ♀ |
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| Scientific name | ||||||||||||
| Circus aeruginosus | ||||||||||||
| ( Linnaeus , 1758) |
The marsh harrier ( Circus aeruginosus ) is a Palearctic bird of prey art from the family of Accipitridae (Accipitridae). Their brood distribution extends from central Mongolia to Portugal and from Scandinavia to North Africa. The wintering areas are in West and Central Africa, Arabia and the Indian subcontinent. The species inhabits reed stands, moors, lake shores and other wetlands in open countryside, but also grain and rapeseed fields. The marsh harrier's breeding season is between April and August, depending on the latitude, with two to seven eggs being hatched in a ground nest in high vegetation. A distinction is made between two subspecies, with the nominate form inhabiting the north of the distribution area and the subspecies Circus aeruginosus harterti in Morocco , Algeria and Tunisia .
The decline in extensively farmed agricultural areas, the draining of swamps and the hunting of stocks in the 19th and 20th centuries, especially in more densely populated parts of the distribution area, initially led to a sharp decline in stocks, which the marsh harrier was able to catch up after 1950. The total worldwide population is estimated at around a hundred thousand individuals.
features
Physique and plumage
The Marsh Harrier is 48 to 62 cm long, almost the size of a buzzard, but noticeably slimmer and narrower-winged. The wingspan is up to 130 cm. The average weight of the males is 540 g, that of the females 740 g.
The larger and heavier female has dark brown plumage throughout and a light yellow head. With them, the shoulders and the front wing are whitish to light yellow. The skull and throat are colored similarly. A dark line runs through the eye to the back of the head.
In the russet male, the middle areas of the wings are silver-gray, the wing tips black. The thrust (tail) is long and gray, the head light gray with dark dashed lines.
The Marsh Harrier is stronger and more broadly winged than other harriers. When sailing and gliding, like all consecrations, she holds the wings up in a V-shape.
Appearance of the nestlings
The marsh harrier cubs are nestled with down only on their head, body and thighs. In the first down dress, the pink skin still dominates. In newly hatched Marsh Harriers, the upper bill is black and the lower bill is flesh-colored to pink. The tip of the beak is black. The wax skin and the beak edges are slightly reddish cream-colored. With increasing age, the wax skin, the beak edges and the legs change color to yellow. The bare skin around the eye turns blackish gray. The beak turns completely black. During the color change process, the base of the beak is initially pale blue-gray before it also turns completely black.
voice
The lapwing-like marsh harrier calls can only be heard in the vicinity of the breeding site, especially shortly after arriving from winter quarters. They are mainly used for courtship or territorial defense. When singing, the male lets out a nasal hijäe , quiä or kjäh . Compared to rivals in the area, the reputation is softer and sounds nasally good . Females give a hoarse and quiet psie ... when taking prey .
distribution
The Marsh Harrier is widespread as a breeding bird over North Africa , Europe and Asia . The main focuses of the settlement areas are in the lowlands of Russia and Northern and Central Europe . The Marsh Harrier is a characteristic bird of extensive reed beds .
The Marsh Harrier is a short and long-distance migrant. Winter roosts can be found in south-western Europe and the Mediterranean region, in Romania and in the south of Ukraine, in front and rear India, Sri Lanka and Sumatra. In Africa it partly winters south of the Sahara and can also be observed in the winter months in the north of Angola, in the Congo Basin, Tanzania, Zambia and Zimbabwe. In Central Europe there are no winter marsh harriers except in the Netherlands. The withdrawal of the adult birds begins in late July and early August. The directional move, however, does not begin until mid-August. Marsh harriers then leave their wintering quarters again in the period from February to April. In Germany, the breeding birds return from mid-March, in Fennoscandinavia the return of the breeding birds takes until the beginning or mid-April.
habitat
The marsh harrier is more closely tied to reeds and reeds in its way of life than other harriers. In recent decades, however, there has also been an increasing number of breeding in cereal and rapeseed fields. They prefer to hunt over the reed belt and the subsequent silting zones. But it also hits prey in dunes and meadows. The Marsh Harrier usually rests in wetlands on the train. But it can then also be seen regularly on agricultural land.
nutrition
The marsh harrier's strategy is to take its prey by surprise in a low “rocking” search flight with V-shaped wings. It usually takes prey close to the ground, less often on the water or in the air. 70–80% of the prey is made up of songbirds and (mostly young) waterfowl such as ducks , pond and white claws . During the breeding season, it mainly beats chicks and nestlings and also eats eggs the size of magpies eggs. Depending on the availability, the main part of the food can also consist of field mice, brown rats, ground squirrels, young rabbits and hares as well as muskrats. In addition, fish, frogs, lizards and large insects also belong to the food spectrum to a small extent. The Marsh Harrier also goes to carrion and occasionally hunts prey from other birds.
Although birds are part of their diet, the marsh harrier is rarely found plucking . It works its prey where it struck it. These are not infrequently open spaces in reed beds or on stilts. Unlike a number of other birds of prey, it has no fixed plucking places.
Courtship
From March / April, the male's impressive acrobatic courtship flight can be observed: mock attacks against the female, dives and sudden sideways tilting followed by a nosedive serve to bond the partners.
Brood
The nest is usually built in dense reed beds above the water or between marsh plants directly on the ground. Nests are sometimes made in grain fields, rarely in meadows. The nesting place is re-used by some couples. The nest is a large heap of sticks, old reeds and similar materials. It is greater than that of other ordinations. The female is almost exclusively involved in building the nest.
Marsh harriers only raise one clutch per year. In Central Europe, eggs are laid from the beginning of May and can drag on until June. The typical full clutch consists of four to five eggs. Very large clutches can also consist of eight eggs. The eggs are short elliptical with a smooth shell that is dull. The egg shell is bluish white and often discolored by the nesting material during the breeding season. Only the female breeds and is fed by the male during this time. The incubation period is 31 to 36 days.
The hatching distances between the individual young birds are different. During the first seven to ten nestling days, the young birds are huddled intensely by the female. During this time, too, the male alone brings food to the nest and also takes care of the female. The prey is given to the female in flight or on the ground. As the nestlings get older, both parent birds hunt for food. The nestlings are fully feathered at 21 to 28 days and are able to fly from their 35th to 40th day of life. They stay near the eyrie for the first fourteen days after the excursion. It usually takes another 2-3 weeks for them to become fully independent.
Systematics and history of development
After all members of the marsh harrier complex, with the exception of the frog harrier, were only regarded as subspecies of the European marsh harrier until the 1970s , only two subspecies are recognized today:
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Circus aeruginosus aeruginosus - ( Linnaeus , 1758)
- Nominate form with distribution from Central Asia to Western Europe.
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Circus aeruginosus harterti - Zedlitz , 1914
- Edge of the Atlas Mountains in Morocco, Algeria and Tunisia. Males with a darker upper surface, but lighter, silver-gray wings and control feathers. Females with uniformly cream-colored heads, necks and shoulder pads, but lighter brown in the rest of the plumage. With wing lengths of 375–487 mm (males) and 401–424 mm (females), slightly larger than the nominate form.
Duration
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Since the end of the 19th century, the marsh harrier population has been greatly decimated by shooting down, stealing eggs and destroying the breeding grounds. Since the early 1970s, however, the population has been increasing again. This is attributed to the year-round protection and the ban on the use of DDT . The species is still endangered by the progressive destruction of the habitat (draining of wetlands) and by disturbance of the breeding areas by humans. The high population pressure in Central Europe has also led to the colonization of agricultural areas and arid areas. It now also occurs in low mountain ranges up to 750 meters in altitude.
As with other consecrations, a change or loss of habitat, for example through regulation of flowing waters, lowering of the groundwater level and drainage, is a threat to the existence. The Marsh Harrier, however, benefits from the construction of water reservoirs in low-lying areas or the embankment of coastal areas.
At the beginning of the 21st century the total population was estimated at 93,000 to 140,000 breeding pairs. In Central Europe about 20,000 to 25,000 breeding pairs breed. The main distribution area in Europe are the lowlands of European Russia, where between 40,000 and 60,000 breeding pairs occur, as well as the Ukraine with 14,000 to 24,000 breeding pairs. In Germany around 4,400 to 6,630 breeding pairs were breeding at the beginning of the 21st century, in Austria there are 300 to 400 breeding pairs. Poland has the largest Central European population with 6,500 to 8,000 breeding pairs. In Liechtenstein and Switzerland, the Marsh Harrier has not yet been a regular breeding bird.
The species is listed in Appendix I of the EU Birds Directive and is therefore also protected at European level. According to Article 4, Paragraph 1 of this guideline, the member states must designate the most suitable habitats in terms of numbers and area for the conservation of these species as protected areas for the Natura 2000 network .
literature
- Hans-Günther Bauer, Einhard Bezzel and Wolfgang Fiedler (eds.): The compendium of birds in Central Europe: Everything about biology, endangerment and protection. Volume 1: Nonpasseriformes - non-sparrow birds , Aula-Verlag Wiebelsheim, Wiesbaden 2005, ISBN 3-89104-647-2
- Leslie Brown, Emil K. Urban , Kenneth B. Newman: The Birds of Africa. Vol. 1 . Academic Press, 1988, ISBN 0-12-137301-0 , pp. 301-302.
- Stanley Cramp , KEL Simmons (Ed.): The Birds of the Western Palearctic. Vol. II: Hawks to Bustards. Oxford University Press, Oxford 1980, ISBN 0-19-857505-X .
- James Ferguson-Lees, David A. Christie: Raptors of the World . Houghton Mifflin Harcourt, 2001. ISBN 0-618-12762-3 .
- Benny Génsbol , Walther Thiede : Birds of prey - all European species, identifiers, flight images , biology, distribution, endangerment, population development , BLV Verlag Munich, 1997, ISBN 3-405-14386-1
- Urs N. Glutz von Blotzheim , KM Bauer and E. Bezzel: Handbook of the birds of Central Europe. Volume 4: Falconiformes. AULA-Verlag, Wiesbaden 1989, ISBN 3-89104-460-7 .
- Theodor Mebs : European birds of prey - biology - population conditions - endangerment of the population Franckh-Kosmos Verlag Stuttgart 2002, ISBN 3-440-06838-2
- Torsten Ryslavy, Outstanding mass sleeping place for marsh harriers in the European bird sanctuary (SPA) Belziger Landschaftswiesen in 1999 , in: Nature conservation and landscape care in Brandenburg - Articles on ecology, nature and water protection , Brandenburg State Environment Agency (ed.), Volume 9 4, 2000, pp. 136-139. online, pdf
- Robert E. Simmons: Harriers of the World: Their Behavior and Ecology . Oxford University Press , 2000. ISBN 0-19-854964-4 .
Web links
- Videos, photos and sound recordings of Circus aeruginosus in the Internet Bird Collection
- Literature on the Marsh Harrier on the Global Raptor Information Network
- Age and gender characteristics (PDF; 5.7 MB) by J. Blasco-Zumeta and G.-M. Heinze (eng.)
- Circus aeruginosus inthe IUCN 2013 Red List of Endangered Species . Listed by: BirdLife International, 2012. Retrieved October 20, 2013.
- Marsh harrier feathers
Individual evidence
- ↑ a b c Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0-00-713039-2 , p. 88
- ↑ Hans-Heiner Bergmann; Hans-Wolfgang Helb; Sabine Baumann; The voices of the birds of Europe - 474 bird portraits with 914 calls and chants on 2,200 sonograms , Aula-Verlag, Wiesbaden 2008, ISBN 978-3-89104-710-1 ; P. 145
- ↑ a b c Bauer et al., P. 323
- ↑ a b Bauer et al., P. 324
- ↑ Wolf-Dieter Busching: Introduction to plumage and plucking , Aula Verlag, Wiebelsheim 2005, ISBN 3-89104-695-2 , p. 129
- ↑ Cramp & Simmons 1980 , p. 105
- ↑ Brown et al. 1988 , p. 364.