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Aves, 40/1-4 | 2003 | 176-178

  Wintering of Black Storks (Ciconia nigra) from the Czech Republic in different parts of Africa.
Bobek, M., Pojer, F. Peske, L. & Simek, J.

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Adult Black Storks fitted with satellite (PTT) and VHF transmitters in the Czech Republic in 1995-2000 flew to their wintering grounds both along the south-west migration flyway (six birds out of ten) and along the south-east one (four birds). One of the south-west migrants spent the winter in southern Spain, in the Guadalquivir estuary, whereas all others reached their main wintering grounds in sub-Saharian Africa in a bel approximately designated between 16° N and 5° N. Wintering grounds were located in different habitat types : in dry Sudanese savannah, in moist savannah of the Guinean type and in quite different Ethiopian highlands. Several expeditions have been carried out to explore five different wintering grounds. Three storks were successfully monitored in consecutive years (female Kristyna even four times) and all of them showed strong winter site fidelity in terms of few hundred square kilometers. Depending on the migration route, storks arrived to their main wintering grounds from late September till early December, however arrival was variable also for repeatedly monitored storks. A “buffer zone” in western and central Africa at the southern edge of the Sahara was found. In that zone storks aggregated into more numerous groups up to few dozens of individuals. Some storks stayed for the whole winter period in such areas, mainly in western Africa in inundated areas of the Senegal River in the Maghama region, Mauritania-Senegal border (probably also the Karakoro river area, Mauritania-Mali border). Other storks can use the zone for resting and feeding to restore fat reserves before continuing their journey to thier main wintering grounds. However, increasing competition for water resources as has been showin in eastern Chad can induce such continuing migration. Main wintering grounds of storks from the south-west migration group were localized in eastern Segenal, central and western Mali and in southern Mauritania. The south-east migrating storks finished their migration in northern Ethiopia, eastern part of Central African Republic (two birds) and in south-eastern Nigeria. Only short local movements up to few dozen kilometers were recorded at main wintering grounds where storks spent the winter season solitarily or in small groups. Several expeditions monitored different threats to wintering storks. Besides the above mentioned competition (both with wildlife and people with their livestock) for quickly drying water resources, main conflicts arise from wintering in areas of dense human settlment, where storks can become victims of vandalism (Ethiopia) or, may be, evev of intended hunting (Nigeria). Lack of appropriate habitats for Black Storks is closely connected with expansion of agricultural lands. Tracked birds left their winter grounds from mid-February till late March. Short-distance and two long-distance (520 km from western Mali to northern Sierra leone and 960 km from eastern Senegal to northern Ivory Coast, repectively) movements were found just right before return migration. Such movements were probably forced by drying of feeding sites. The Black Stork is one of the threatened European bird species. Therefore it should be appropriate to ensure effective protection of sites and habitas where higher stork aggregation occur in winter grounds. It would be very useful to declare the above-mentioned Maghama area in southern Mauritania, which is an important stopover site as well as a main wintering ground for many Black Storks, as specially protected area.

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