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Other roosts: In foraging areas and their wider surrounding other roost sites are visitedwhich give cover for resting and from bad weather (Ruedi 1993) or have a social function(Haensel & Ittermann 1998).Foraging areas: Foraging areas are predominantly at open water bodies and slow flowingrivers (Austria: Spitzenberger 2001, Denmark: Baagøe 2001a, Fennoscandia: Jensen 1993,Germany: Zahn & Maier 1997, Boye and others 1999, Kretschmer 2001, Greece: vonHelversen & Weid 1990, Hanak and others 2001, Hungary: Dobrosi n.y., Italy: Spagnesi andothers 2000, Luxembourg: Harbusch and others 2002, Poland: Kowalski & Ruprecht 1981,Woloszyn 2001, Spain and Portugal: Benzal and others 1991, Switzerland: Moeschler &Ruedi 1995, The Netherlands: Limpens & Kapteyn 1991). Daubenton’s bat prefers waterswith trees or bushes on the banks so that not all the water surface is disturbed by winds(Spitzenberger 2001, Dietz & Boye 2004). The foraging success is also influenced byduckweed on the water (Boonman and others 1998). Sometimes, mainly in springtime, thebats also forage away from water, e.g. at a clearing in woodland. The use of particularforaging areas generally follows the abundance of Nematocera and Ephemeroptera (Dietz1998, Kretschmer 2001). If prey abundance at the waters is reduced due to windy weather orcold nights Daubenton’s bat forages instead in woodlands (Zahn & Krüger-Barvels 1996).In oak forests individual home ranges were identified with an average size of about 49hectares. Core areas within the home ranges are dependent on the size and structure of thewater bodies and have sizes between 100 square metres and 7,500 square metres (Meschede& Heller 2000).The results of investigations with telemetry and ringing show that Daubenton’s bat is amobile species which can cover distances between the roost and foraging areas of 7-8kilometres without difficulty. On the way from the roost to a hunting ground the batsorientate along landscape structures, which mark the flight path (Ebenau 1995, Dietz &Fitzenräuter 1996, Klenk and others 1996, Rieger 1997, Kretschmer 2001).Abundance: In a lake district in northern Bavaria (Germany) the summer abundance ofDaubenton’s bat was investigated by a capture-mark-recapture experiment on a 40 squarekilometre plot. The result was an estimation of 30-40 individuals per square kilometre (vonHelversen 1989).3.4 Whiskered bat Myotis mystacinusForest habitats: The wide range of summer roost sites and foraging habitats includes avariety of forest types all over Europe.Summer roosts: Summer roosts are in crevices and holes in buildings, in tree holes, andbehind loose bark (Tupinier & Aellen 2001). In many cases the entrance to a roost is a verysmall opening (Nyholm 1965). Bird or bat boxes are used by single individuals or as matingroosts (Meschede & Heller 2000), only occasionally are boxes used by a maternity colony(Häussler 2003).Brandt’s bat and the greater mouse-eared bat have been observed in maternity colonies ofwhiskered bat (Tupinier & Aellen 2001, Boye 2004).21