Micro-Habitat Nest Preferences of the Great Bittern,Botaurus stellaris, on Fishponds in Central-Eastern Poland

Habitat quality and breeding parameters in relation to female mating status in the polygynous Eurasian Bittern Botaurus stellaris

“…Habitat use by the Eurasian Bittern population in this study was corroborated by studies carried out in the UK, which found that the male's home-range encompassed on average 30 % open water and 48 % reed edge (Gilbert et al 2005b). The lack of influence of other microhabitat parameters on nest clumping is due to stable nest preferences within a particular patch of emergent vegetation (Polak et al 2008). The remaining micro-and macrohabitat parameters (water depth, number of new and old reed stems, distance to the dyke and distance to open water) were the same for single and clumped nests.…”

“…The remaining micro-and macrohabitat parameters (water depth, number of new and old reed stems, distance to the dyke and distance to open water) were the same for single and clumped nests. Some habitat variables that affect the selection of nesting positions, regardless of female status, appear to be crucial for Eurasian Bittern females (see Adamo et al 2004;Gilbert et al 2005a;Polak et al 2008). Besides the anti-predator role of habitat components (Polak 2007), the most important factor causing daily losses of Eurasian Bittern chicks was starvation (Gilbert et al 2007).…”

“…In eastern Poland, fish farms with dense, small-bodied fish populations and a large coverage of only occasionally cut emergent vegetation have a bird-friendly fish management and may still support a relatively high waterbird species richness. For a detailed description of the habitat, see Polak et al (2008). The density of the Eurasian Bittern breeding populations in the study area ranged between 1.1 and 12.5 inds/100 ha for males, and between 1.1 and 20.0 inds/ 100 ha for females; this is the largest density recorded in Poland (Polak and Kasprzykowski 2009).…”

“…Six different habitat variables were analysed: water depth (WATER); two microhabitat variables: the number of dry (OLD) and green (NEW) reed stems within a nest square; and three macrohabitat variables: the distance to open water (DISTOW), the distance to the fishpond dyke (DISTDYKE) and the proportion of open water area to emergent vegetation area (PROARE). Providing a very good description of the Eurasian Bittern's habitat preferences, these variables may determine some of this species' breeding parameters in a specific semi-natural habitat like fishponds (Polak 2007;Polak et al 2008). In particular; the proportion of open water area to emergent vegetation area is a much better habitat descriptor of a fishpond than other macrohabitat components like water edge, which are important for populations living in more natural habitats.…”

Water on the Fen Mire as a Problem in the Protection of Globally Threatened Species: Long-Term Changes in Aquatic Warbler Numbers

“…In May and June, when AWs start to breed, the water reaches its optimal level of a few to a dozen or so cm [3,8]. The water level in the breeding locality and its periodic fluctuations are extremely important factors as regards breeding success of AW and other bird species [28][29][30][31]. The results from Belarus indicate that sudden changes in water level due to heavy rainfall can cause nests to be flooded and therefore lost [8].…”