Ardea
Official journal of the Netherlands Ornithologists' Union

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Polak M. (2007) Nest-site selection and nest predation in the Great Bittern Botaurus stellaris population in eastern Poland. ARDEA 95 (1): 31-38
This study analyses the effects of nest-site selection on predation risk of Great Bittern Botaurus stellaris nests. The study was conducted in fishponds of eastern Poland during four breeding seasons (200306). The habitat characteristics of 84 nest sites were investigated. Nesting sites were found within Phragmites, Typha, Carex and Scirpus vegetation in the reed belt surrounding the fish ponds. All nests were built at places having between 10 and 97 cm of water depth. Predation was the major cause of nest failure in the study population. However, no relationship between nest site vegetation type and daily nest survival rate was found. The survival of nests at edges and in the interior of reed beds was similar. A logistic regression model indicated significant effects of water depth and vegetation cover on nest predation in the Bittern population. There was a tendency towards better success for nests in dense emergent vegetation with higher water depth. The results have important implications for an effective conservation strategy for wetlands holding large and viable populations of this vulnerable species.


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