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Aves, 20/1 | 1983 | 1-24

  Increase of Great crested Grebe (Podiceops cristatus) nesting in Wallonia and Brabant.
Jacob, J.-P.

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Article summary

The Great grested Grebe has been nesting in Brabant since 1935 and in Wallonia since 1940. A first phase of development was observed between 1940 and 1946. Later on, its population growth increased enormously since the end of the nineteen fifties. Surveys carried out in 1980 and 1981 resulted in 419 and 426 adults respectively, of which 62-66 % were nesting (130 pairs in 1980 and 141 in 1981). Half of the grebes were concentrated in Brabant, and other populations worthy of note were found in the River Haine valley, and in the zone between the Rivers Sambre and Meuse. The Tournai region has recently been colonised and the presence of a few individuals is tending to stabilise east of the River Meuse. The increase is mainly the result of the protection of the species, its reduced exigencies, the development of ponds for fish-breeding and for fishing and the eutrophisation of certain streches of water. The fish-breeding and fishing ponds attract most of the birds, the others being distributed on quarry ponds, park lakes and lakes resulting from dams. The great crested Grebe was first of all limited to fairly extensive stretches of water surrounded by reeds. Since then, it has adjusted itself to ponds of a smaller size (even less than 2.12 acres = 1 hectare), and even without vegetation on their sides. This evolution is similar to that observed in the neighbouring countries and regions. Comparison of the surveys made in May and June 1980-1981 shows early departures of the adults (26 % in 1980 and 17 % in 1981), mostly non-nesting birds. This phenomenon is earlier than generally accepted.

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