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Fauna

THE BIG BITTERN OF BOTAURUS STELLARIS LINNAEUS, 1758 CHAPLYA-BUGAY, VYALIKI BULL

Number and tendency of its change:
Considerable reductions of number and area of distribution of a look in Europe occurred at the beginning of the 1900th, then in 1970th and 1990th. Large-scale drying melioration, a number of severe winters when the large number of the individuals wintering in Europe, and in some countries also prosecution by the person died were the main reasons for it. Look number in a number of the countries continues to decrease, in some countries is stable or slightly increases. In Belarus the number of a look was significantly reduced probably in connection with the drying melioration which is carried out in 1950-90. Now it is estimated as stable, in 950-1200, according to other data - 1000-1800 tokuyushchy males that makes about 5% of the European population. In favorable conditions density makes to 14 vocalizing males on 1 sq.km of thickets of reed and a rogoz.

Habitats:
- pond of fish farms
- long rivers
- lakes
- bogs with sites of open water

Major factors of threat:
- a burning out of a dry trostyonik and a rogoz during the spring period
- strong differences of water level during the reproduction season
- death in traps
- destruction of nests land predators and vranovy birds

Protection measures:
The look is included in the Red List of Republic of Belarus since 1981. The part of the territories important for the sake of appearances, is protected in system of especially protected territories. Key ornithological territories (IBA), the most important for maintenance of the Belarusian population of a look which parts the security status is required to give are revealed and established. Rigid control over a burning out of wetland vegetation and over the number of vranovy birds is necessary.

Description of a look:
Heron of average size, sturdily-build. Length of a body is 62-80 cm, weight - about 1,3 kg. The head is quite massive, legs rather short, fingers very long. Wings are wide, roundish, a tail short. Main coloring of plumage yellowish-brown, motley. Top of the head and moustaches black. Beak and legs chartreuse. A naked bridle brown, at males during a marriage season - blue.

Distribution:
The nominative subspecies which area passes through all Eurasia from east coast of Atlantic to the Pacific Ocean live in Belarus, without coming to the north of 60 degrees of a northern latitude. In Belarus the look is widespread on all territory, but unevenly. In the east of the country meets rather seldom.

Biology:
Migrating nesting flying and tranzitno, it is single the wintering look. A big bittern - a bird quite reserved, however it is possible to see it in the afternoon flying over water or vegetation. In twilight sometimes flies circles over a reservoir with characteristic shouts to "ka". During the nested period males let out very loud deaf cries "up-boom" repeating 2-9 time in a row and which are well heard at distance of 1-2 km, but sometimes - to 6 km. The beginning of vocalization of a bittern is noted in the second decade of March - the beginning of April, depending on the region of the country. The big bittern of a poligamn, in the territory of one male can be to five nests. The male does not participate in cultivation of posterity. The nest is under construction on any support or directly on water between stalks of reed or a rogoz. Otkladka of eggs begins in the second decade of April and generally comes to an end in the second decade of May. In a nest usually 4-6, seldom 3-7 eggs. Eggs greenish-gray, without gloss, the sizes on average 52,6 × 38,6 mm. Nasizhivaniye lasts about 25 days, begins with the first or second egg. Hatching of baby birds asynchronous, lasts for 4-12 days. Baby birds rise by a wing at the age of 7-8 weeks. As the main forage for a big bittern serves fish, large water insects, Amphibia, but also mouse-like rodents and other small animals meet. Autumn flying away is strongly dragged out, takes place from July to November, but, probably, the bulk of birds migrates in September.

Article from the Red List of RB


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