Research
Wright, P.G.R. et al. (2022). Effect of roost management on populations trends of Rhinolophus hipposideros and Rhinolophus ferrumequinum in Britain and Ireland
Species Lesser Horseshoe Bat
Facts about lesser horseshoe bats
- English name: Lesser horseshoe bat
- Scientific Name: Rhinolophus hipposideros
- Number of young: One, called a pup, born mid June to early July.
- Diet: Small insects including midges, moths, craneflies, lacewings.
- Habitat: Summer roosts in old, generally uninhabited buildings; winter roosts in caves, cellars and mines; forages in deciduous woodland and in riparian vegetation.
Distribution and status
Once found across southern England and as far north as Yorkshire, following a widespread decline across Europe in the 20th century, the lesser horseshoe bat is now restricted to Wales, the West Midlands, southwest England and western Ireland. The populations in Britain and Ireland are now internationally important.
Horseshoe bats with their peculiarly shaped nose-leaves, have faces that differ from other bat species in Britain and Ireland. They also, unlike other bats, wrap their wings around their body while asleep and usually hang free from their feet when roosting. There are two species of horseshoe bat in Britain and Ireland — the greater horseshoe bat and the lesser horseshoe bat.
In Ireland, only the lesser horseshoe bat is present.
This tiny and delicate bat, with its butterfly-like flight, suffered a widespread and catastrophic decline in Europe during the 20th century, although it is now showing some signs of recovery. Against this background, the populations in Britain and Ireland are now internationally important. The lesser horseshoe bat is much like the greater horseshoe bat in appearance, but is about a third of the size, making it one of our smallest bats.
During the summer, lesser horseshoe bats usually prefer to roost in old, undisturbed stone buildings with slate roofs and large entrances that allow flight into the roost spaces. In winter, they usually hibernate in caves, mines, cellars and ice houses.
The summer maternity roosts are usually in the roof spaces of old, disused buildings, churches or farm outbuildings and are used each year by the same colony. This species may also use smaller satellite roosts in the locality.
Lesser horseshoe bats may also colonise purpose-built bat towers. Examples of these are at a number of VWT's bat reserves. They have also been built in collaboration with farmers along the River Mulkear in Ireland as part of a European Innovative Partnership project with the Mulkear River Catchment Project in Co. Limerick.
Generally, lesser horseshoe bat winter roosts are within 5km of the summer maternity roosts, but occasionally some will travel up to 20km to hibernate. Most winter roosts are just used by a few bats, though some support colonies of around 400 bats. Unlike greater horseshoe bats, lesser horseshoe don't cluster in hibernation but stay slightly apart from each other.
Lesser horseshoe bats mainly eat small flying insects such as midges, but they also take crane flies, moths and caddisflies.
Lesser horseshoe bats become active in their roosts at dusk and will often make short 'test' flights outside before finally flying to their feeding areas. They will fly low to the ground or hug the walls of buildings until they reach the nearest cover of vegetation such as hedgerows and tree lines as they fly to deciduous woodlands to hunt, catching insects in flight or picking them off foliage. Occasionally, they will take prey from the ground or will hang from a perch to catch passing prey.
Most female lesser horseshoe bats first give birth in their second year, although exceptionally one-year-old animals have been recorded giving birth. The males do not become sexually mature until they are one year old.
Most mating takes place during the autumn and winter but fertilisation doesn't happen until the following spring — the females are able to store the sperm until conditions are right to allow fertilisation and birth during warmer weather and when food is more abundant.
The single pup is born in late June or early July. In the first few days, it may be carried from the roost at night when its mother goes out hunting. Not all females of breeding age give birth every season; in some years as few as one third produce young. Infant mortality can be very high, especially if weather conditions during late pregnancy and lactation are poor. These factors contribute to a very low reproductive rate, with the result that populations may take many years to recover from adverse events. Following birth, the young grow rapidly and achieve independence after four to five weeks. Juveniles may remain in the maternity roost until late September, after the mothers have left.
A combination of habitat loss; loss of roost spaces as old buildings are converted to modern homes; agricultural intensification including use of insecticides and loss of hedgerows; and increases in urbanisation — resulting in increased light pollution and noise disturbance has led to a dramatic decline in lesser horseshoe bat numbers.
VWT has acquired a number of old buildings that are managed as lesser horseshoe bat roosts in Wales, southwest England and western Ireland. The surrounding landscape is also managed to provide shelter and food. VWT Ireland is also working with local councils to take lesser horseshoe bats into consideration with regard to new developments and lighting.
VWT's work
VWT works to conserve lesser horseshoe bats through the following actions.
- Establishing bat roost reserves in Britain and Ireland;
- Annual monitoring of horseshoe bats in roosts;
- Regular work to secure, maintain and future-proof hibernation and summer roosts against predators and impacts of climate change;
- Major studies of the roosting and foraging ecology of the species;
- Assessing foraging areas and commuting routes surrounding key lesser horseshoe bat breeding roosts;
- Surveying buildings in southwest England, the West Midlands, Wales and Ireland for undiscovered horseshoe bat roosts;
- Delivering training workshops around its reserves
- Producing a Lesser Horseshoe Conservation Handbook to inform ecological consultants and Statutory Nature Conservation Organisations (SNCO);
- Collaborating to achieve a Species Action Plan for lesser horseshoe bats in Ireland.
Species Action Plan for Lesser horseshoe bats in Ireland
The lesser horseshoe bat has been awarded a Species Action Plan to bring together effective and efficient conservation actions to protect this rare species in Ireland.
FAQs about lesser horseshoe bats
The lesser horseshoe bat needs a mosaic of well-connected habitats in which to feed, easily accessed and undisturbed structures in which to roost, and dark areas to fly along. An Action Plan brings together the range of organisations who can provide these conditions. Local authorities with responsibility for roads and urban development; government departments and agencies with responsibility for biodiversity, agriculture, and forestry; and environmental groups who conduct research, monitoring and education are just some of the partners working together to conserve the species.
Compared to other Irish bat species, the lesser horseshoe bat flies relatively slowly through the landscape, which makes it easier for predators, such as sparrowhawks, to predate them. They therefore avoid flying in open areas until natural light levels decline, but they also avoid areas with artificial light. The increase in the level of artificial light in the landscape is restricting how lesser horseshoe bats can safely access suitable roosting and feeding areas.
We conducted modelling projects for four local authorities, which identified some key features or locations that would enable the species to move safely through the landscape. One council subsequently used this information to alter its plan for the location of new artificial lights.
Keep old buildings old and accessible, plant hedgerows, have a diversity of plants in gardens to attract insects, and try hard to keep the countryside darker for bats through the use of more bat-friendly artificial lighting systems.
Further reading
[Archive Projects]
Impacts of Street Lighting on Bats and Our Beacon for Bats
The Impacts of Street Lighting was a collaborative project with University of Exeter that ran from 2012 to 2015 and focused on the responses of bats and their invertebrate prey to artificial night-time lighting. The Our Beacon for Bats Project involved local people in helping to find out more about lesser horseshoe bats in the Usk Valley
