lesser horseshoe bats
Identification
The lesser horseshoe bat (Rhinolophus hipposideros) one of the smallest UK bats. They weigh around 4-9 grams (the size of a plum) with a wingspan of 225-250mm. Lesser horseshoe bats are one of only two species of Rhinolophus (horseshoe) bat in the UK, which are characterised by the horseshoe shaped nose leaf around the nostrils. They hang freely from their feet often with thier wings wrapped around their body.
Biology
Lesser horseshoe bats echolocate through their nostrils and the disc like shape of the noseleaf is thought to increase the directionality of echolocation calls. With very short wings lesser horseshoe bats are highly maneuverable in flight prefering to fly close to vegetation (Dietz et al. 2006).
Mating occurs in the autumn and females store the semen over winter, giving birth to a single young during June and July (Schober & Grimmberger 1993). Juvenille bats are characterised by grey coloured fur and emit lower echolocation calls than adults (Jones et al. 1992). Females often carry juvenilles with them during foraging trips just after birth. Juvenilles are held upside down by their mothers, grasping on to the pelvic nipples with thier teeth (Schofield 2008). Young become independant at five weeks (Scholfield & Mitchel-Jones 2004) and live for on average of seven years (Harmata 1992).
Roosting Ecology - Summer Roosts
Lesser horseshoe bats mainly roost in buildings during the summer months (May - Sept) prefering 16th century buildings, often with stone walls, slate roofs and uninterupted flight access (Schofield 2008). During this time some bats will occasionally use alternative day roosts (satellite roosts), but the colony as a whole will remain in the same roost (Knight 2006). Research suggests that this occasional roost switching may be related to the energetics of breeding (Seckerdieck et al. 2005).
Bats also use night roosts away from the maternity roost inbetween foraging bouts. These are often in buildings and located within 1-2km of the maternity roost (Knight 2006). It is believed that night roosts are used to minimise energetic losses during periods of reduced prey availiability (Anthony 1981) or in periods of high energetic demand when females are heavily pregnant. It is also suggested that night roosts are used to facilitate information transfer between individuals (Kunz 1982; Wilkinson 1992).
Roosting Ecology - Hibernation Roosts
Lesser horseshoe bats hibernate during the winter in underground caves, mines and cellars, which are humid (reducing the need to drink) and range between 4-12 degrees celsius (Ransome 1991). Hibernation roosts are typically within 5km of the maternity roost but on occasion have been 20km away (Schofield & Mitchel-Jones 2004). Bats are not in a static state throughout hibernation, often waking to feed and drink during the spring and autumn (Ransome 1991).