Great Reed Warbler
Great Reed Warbler (Acrocephalus arundinaceus )
The great reed warbler (Acrocephalus arundinaceus ) is a passerine bird in the genus of warblers (Acrocephalus ) and the family of reed warbler -like ( Acrocephalidae ). There are two subspecies. In Central Europe, the great reed warbler is a common regional basis, but only locally common breeding and summer bird.
Description
The great reed warbler is about 19 cm long and has a wing length of 9 cm, the largest of all Central European warbler species. The weight is about 25 to 36 grams. The top is brown, yellowish white its underside. The bird has a whitish throat, a sharp beak and an indistinct white eye-streak over. Males and females have the same coloring. His call sounds like " Kaare Kaare krieht krieht " to mark his Revieres.
Distribution and habitat
The distribution area of the throttle tube singer extends from northwest Africa, Portugal and Spain to north- eastern China, the southern part of Sakhalin and northern Japan. In Central Europe, the great reed warbler was originally used in the lowlands up in some upland areas. Since the 1970s it came to the part to very drastic stock declines. He has since been on widespread gaps and is only in the north - and south- central Europe a common breeding bird.
In most of Europe the long-distance migrant from April to September is present. He has in tropical and southern Africa, His winter quarters. Check-out time and the pulling direction are innate. The Reed Warbler lives in the dense reeds and bushes shore of lakes, ponds, swamps and rivers. Ideal habitats are reed and reed - bulrush - mixed stands that are three to six years old and have stalks of more than 6.5 millimeters in diameter. Per square meter should be between 34-62 straws. The most common warbler can be found in at least five meters wide reed belts on larger standing water.
Nutrition
The Reed Warbler climbs and jumps sent in the reeds and feeds on spiders, mollusks, insects, their larvae, young amphibians and berries.
Reproduction
Sexual maturity occurs after one year. The main breeding season is May to July. The cup- of grasses and reeds woven nest is usually fixed in the protection of reed-beds between three to four reeds above the water. The female lays four to six eggs. The eggs are warmed 13 to 15 days. The young birds stay 12 to 14 days in the nest. Cuckoo eggs are often found in the nests of warblers because they have a similar color.
Stock
In Central Europe, the breeding area expanded at the beginning of the 20th century clearly. This was at the onset of eutrophication and an increase in the reeds stock. The ongoing eutrophication of water bodies as well as a partly significant habitat loss through drainage of wetlands led in the 1950s to a decrease in Art This intensified. Since the 1970s For very strong population declines occurred among others in the Netherlands, Belgium, Germany, Czech Republic and Slovakia. For example, the breeding pair population in the Netherlands fell from more than 10,000 breeding pairs in the 1950s to less than 300 breeding pairs in the 1990s. In Luxembourg and large parts of Belgium and Germany individual populations extinct some completely. In the long term largely stable populations are only found in regions such as North Moravia and Poland, where there are large undisturbed reed areas. Since the 1980s, the stocks in Germany and the Netherlands have stabilized at a low level.
One cause of population decline is common to find that the great reed warbler responds more strongly than other warbler species negatively to the silting up of the reed reeds. Eutrophication and use of biocides has also led to the breeding season, the supply of larger insects has decreased. He also sensitive to disturbances at their breeding ground by water sports and other recreation seekers.