Habitat Selection by White Storks Breeding in a Mosaic Agricultural Landscape of Central Poland.

The number of White Storks ( Ciconia ciconia) has been decreasing in many parts of Europe at least since the middle of the 20th century. Intensification of agriculture and continuous conversion of natural habitats, such as wetlands, into agricultural landscapes have been recognized as the most important determinants of dramatic reductions in population sizes of this species. For this reason, providing quantitative estimates of habitat requirements may allow us to identify the key biota which should be prioritized for conservation. The aim of this study was to investigate White Storks' habitat selection in a mosaic agricultural landscape in central Poland. We found that territories associated with large river valleys were highly preferred by first-arriving storks. We also recorded lower intensity of brood reduction and higher reproductive success of storks breeding in such territories. Thus, it seems likely that location of nests close to river valleys provided easy access to rich food resources associated with wetlands. In fact, distance to nearest wetland was the second strongest predictor of nest-site selection in the studied population. We also demonstrated that pairs nesting in the territories with a high proportion of wetlands showed lower levels of brood reduction in comparison to pairs having poorer access to wet habitat patches. Finally, we found that although early arriving storks avoided settling in an urbanized landscape, they selected nesting sites located close to buildings. The results of this study confirmed high importance of wet grasslands for the core central European population of White Storks. [ABSTRACT FROM AUTHOR]