Leisler's bat
Nyctalus leisleri
Status:
The Leisler’s is a native species with an unknown and probably under-recorded distribution in Snowdonia and indeed the rest of Wales. It is widespread in Ireland and occurs on the Isle of Man and in south-west Scotland, so it is puzzling why records are so scarce for Wales. It is also recorded in the English midlands up into Yorkshire and has a stronghold around London. Advances in the use of bat detectors will undoubtedly improve distribution knowledge.
The species has European Protected Species status in the UK and is threatened by loss of roost sites and foraging habitat.
This is predominately a tree bat in Europe. UK nursery colonies are chiefly located in roof spaces of buildings. To date no roosts have been found Snowdonia but it has been recorded in flight using bat detectors.
Like the noctule bat, the species emerges at sunset flying high and fast with aerial hawking for insects over pasture, rivers and lakes, but also around street lights.
Females gather at nursery roosts in early summer (which may exceed more than 300 individuals in roosts recorded in England and Ireland). Females give birth to a single baby in mid-late June and the nursery roost generally stays stable until the juveniles are weaned in August. In the summer males may be more mobile moving between sites and may roost alone or in small groups. However, individual males may establish territorial mating roosts between August and October, where harems of females may also be encountered at this time.
The greatest recorded longevity for this species is 11 years, and this is one of the few species prone to being predated by hobbies and sparrowhawk (possibly because of its relatively early emergence at dusk and high flight)