Bats

Horseshoe bats

Greater and Lesser Horseshoe Bats are named for the horseshoe-shaped fold of skin around their nostrils which is known as a nose leaf (Rhinolophus is Greek for nose crest). This boosts the weak sound waves they emit to navigate, communicate and find food.

Size: Greater Horseshoe Bats are a large bat, around the size of a pear. Lesser Horseshoe Bats are about the size of a plum and one of the UK’s smallest bats.

Roosts: In summer both species roost in warm attics, roof spaces, slate roofed barns and sometimes cellars or boiler rooms. In winter they hibernate in cellars, caves and mines, where temperatures are stable and humidity is high. Both hang upside down in roosts (rather than tucking themselves into crevices) with their wings wrapped around their bodies. Neither species will generally roost in bat boxes or trees.  They can be identified by their droppings which have a distinctive pinch in the middle.

Flight: Both species have weak echolocation calls and so generally stay within 5 m of linear features (so that their calls can bounce back) to navigate around the countryside. This means that they’re low flying and more vulnerable to road collisions than higher flying bats such as Serotines and Noctules.

Lighting: Both species are very light sensitive and will avoid lit areas.

Foraging habitat:

Greater Horseshoe Bats feed on different insects at different times of year. In the spring females feed over pastures eating beetles such as Cockchafers and dung beetles (which live on cow pats). In the summer bats and their young feed mainly on moths and later in the summer craneflies form a key part of their diet. Whilst cattle grazed pastures are important, they also feed in woodlands, wetlands and along hedge corridors and along watercourses – anywhere which is insect-rich.

Adults generally forage within 4 km of maternity roosts whilst juveniles hunt within around 1 km and are very dependent on grazed pasture. The distance that Greater Horseshoe Bats forage from winter roosts is thought to be around 2 km.

Population:

The Greater Horseshoe Bat is rare in the UK and confined to southwest England and south Wales. It’s estimated that the number of bats declined by over 90% in the last 100 years. Reasons for the decline are thought to be due to disturbance to roosts, loss of permanent pastures and lack of insects. The population is now increasing but from very low levels.

Devon holds a third of the UK’s Greater Horseshoe Bat population and many of the larger maternity and hibernation roosts have been designated as SSSIs or SACSpecial Area of Conservation More (South Hams and Beer Quarry and Caves SAC). However, there are a number of large roosts in caves and mines which are not designated. 

Horseshoe bats

See Greater Horseshoe Bat above for information on both species, including roosts.

Foraging habitat

Lesser Horseshoe Bats have very similar foraging requirements to Greater Horseshoes and dung fauna are an important food source for both species. However, Lessers feed on smaller insects (flies, bees, wasps, lacewings and small moths) and have a stronger association with woodland, wet woodland, parkland, scrub and sheltered valleys.

Lesser Horseshoe Bats are weaker flying than Greaters and generally forage within 2.5 km of summer roosts and 1.2 km of hibernation roosts.

Population

The Lesser Horseshoe Bat is rare in the UK and confined to Wales and western England. The population in England is considered to have increased in the long-term (since 1999) and there is evidence to suggest it has declined in the short term since 2018. The population remains vulnerable. Pressures include lighting, changes in connectivity, loss of roosts and a declining insect population.   

Devon is a national stronghold for Lesser Horseshoes, and we have over 30 large maternity roosts. These are found across the county other than the exposed uplands of Dartmoor and Exmoor.  We have a national responsibility to ensure that the population remains robust.

Habitat

This species roosts in crevices in roof spaces in a range of buildings including houses, churches and barns. They usually roost inside the ridge tiles or against the ridge board. Maternity roosts are often in pre-Victorian or Victorian buildings, with large loft spaces. Open-fronted barns form part of their network of day and night roosts. They have never been recorded using bat boxes.

They feed largely on flies and moths (especially the yellow large underwing one of our most abundant large moths which feeds on a range of plants and grasses) in grasslands and wetlands (marshes, ponds, watercourses). They also feed in broadleaved woodland in periods of colder, wetter weather. They largely forage within 5kms of maternity roosts and unlike some species will feed in the middle of meadows as well as around the edges.

Like horseshoes they are very light sensitive.

Population

The Grey Long-eared Bat is the UK’s rarest bat species with a population of around only 1,000 animals and declining. The UK population is thought to be below the minimum size needed to ensure survival and it is therefore classed as ‘endangered’ and at very high risk of extinction.

Maternity roosts are currently only known in Devon, Dorset and the Isle of Wight. Half of the known maternity roosts are in Devon, most within 5km of the coast in south and east Devon.  Devon has a special responsibility for grey long-eared bats, and they are listed as a Devon Special Species.

Grey Long-eared Bats can be confused with the much more widespread and numerous brown long-eared bat which looks very similar and can occupy the same roost. It is therefore critical that DNA testing of droppings in roosts is carried out to identify which species is present. See Find out more for a link to guidance. 

Habitat

Serotines mainly roost in crevices in buildings, often older buildings. They have large oval droppings which are often found around chimney bases or at gable ends of roof spaces. Hibernating Serotines have been found inside cavity walls, and in disused chimneys, and it is possible that they remain in the same buildings used during the summer for some of the winter.  

They feed on a range of larger insects including beetles, flies and moths. They generally feed within 3 km of roosts in a range of open insect-rich habitats such as parklands and wood pasture, traditional orchards and pastures but will also use tree lines, woodland edges and tree lined watercourses. 

Serotines are one of the largest bats in Britain and are strong fliers. They can be seen feeding around treetops in parks, gardens and other habitats as they often emerge when it is still light. They are less sensitive to lighting than other species such as horseshoes and may be seen foraging around streetlights. However, that can still be negatively impacted by lighting which may alter their behaviour as well as increasing the risk of predation.

Population

Serotines are found in southern England and Wales.  The population appears to be stable but is classed as vulnerable to extinction and monitoring by the Bat Conservation Trust has shown that they may be declining (see links in Find out more).  Whilst they are widespread across Devon there is little information about their maternity roosts.

Habitat

Barbastelles roost in crevices in broadleaved woodland trees, often under loose bark, in cracks or deep inside hollow trees during cold weather. They prefer woods with a dense understorey which helps to maintain humid roost conditions, and which form part of a network of woods in a landscape. Barbastelles are very light sensitive.

During the summer female bats will move their maternity roosts (generally 10-20 bats) between trees to maintain optimum temperature and humidity. Roosts (non-maternity) can also be found in old buildings where they use crevice features that replicate their tree roosts.

Whilst Barbastelles will mainly forage in woodlands, they will also use other insect-rich habitats such as meadows (especially wet grasslands and mires), ponds and watercourses.  They are specialist moth hunters but eat other insects such as lacewings, caddis flies and small beetles. Female Barbastelles will return to the same foraging areas on successive nights. Distances that researchers have tracked them travelling to forage range from 6.8 km to over 15 km.

Population

Barbastelles are largely found in southern England and Wales.  The population has declined by 99% over the last 500 years and they are a threatened species.  

Barbastelles are recorded across Devon and are commonly picked up in bat surveys, but in low numbers. A number of maternity roosts have been found on the edges of Dartmoor and between Meeth and Merton in Torridge. There are concentrations of records around east Dartmoor and the coast around Braunton and Bideford. However, there are likely to be roosts in woodlands across Devon which have not been recorded. The Exmoor and Quantocks Oakwoods SAC is partially designated for Barbastelles.

Habitat

Bechstein’s Bats are thought to prefer roosting and foraging in large mature native woodlands where they nest in holes (such as old woodpecker holes) and cavities in trees. However they have also been found roosting in small copses as well as trees in hedges and tree-lines. Males are often found in younger woodland. They prefer woodlands with 50% understorey cover of native species, especially hazel and hawthorn. As for most species little is know about what adult females and juvenile bats do after maternity colonies disperse.

Like Barbastelles they will switch roosts regularly during the summer to find optimum conditions. They hibernate in caves but are likely to also use hollow trees. 

They generally feed in woodlands within a three km radius of maternity roosts and mainly eat moths, beetles, craneflies, lacewings and spiders.

Population

Bechstein’s Bats are confined to southern England with a stronghold in Dorset and are one of the UK’s rarest bats. There are only two known small populations in Devon. However, they have a very quiet call and are difficult to detect.  Beer Quarry and Caves support a few hibernating Bechstein’s Bats, and this is one of the reasons for its designation as a SSSISite of Special Scientific Interest More and SAC. They have been radio-tracked from the caves to maternity roosts around Shute. The only other known roost is near Newton Abbot.