Daubenton's bats, Myotis daubentonii, in the area of the Rhinefalls (S
witzerland) use up to seven day roosts. On an average, they change roo
sts every second day. Some individuals visited two or more day roosts
within 24 hours, others used exclusively the same day roost for more t
han two weeks. Males change roosts twice as often as females. A newly
used day roost is some 600 m away from the old roost. All day roosts i
n a forest are connected with one another by individual roost changes.
Such day roost networks are restricted to one forest. The never found
roost networks with day roosts in different forests. Following rainy
days, Daubenton's bats have a higher tendency to change roosts than af
ter dry days. Our knowledge is too small for a functional description
of day roosts of Daubenton's bats. We distinguish the following day ro
ost types: Type A day-roosts have high animal numbers without much cha
nge from day to day. These day roosts are favourite, based on the numb
er of changes at these roosts. Their entrances are two to five m above
the ground. Bat groups in Type A day-roosts vary during the hunting s
eason. Type B day-roosts have entrances ten m or more above the ground
. 30 to 100 individuals stay together in type B1 roosts. Group size ch
anges daily. Only single animals or a few animals stay in Type B2 day-
roosts, but they use these roosts exclusively for two or more weeks. T
ype C day-roosts have entrances two to five m above the ground. The nu
mber of bats slaying together is small, usually less than 15, quite of
ten less than 6 animals. They stay longer in a Type C roost than in a
Type A roost.