Meet Our Local Bats
The validation of the 2021 and 2022 results of the Bailiwick Bat Survey confirmed the presence of 13 bat species in the Bailiwick
Common Pipistrelle (Pipistrellus pipistrellus)
The Common Pipistrelle Bat is very small weighing around 5 grams which is the same as a 20p piece. Despite their size however, a single Pipistrelle can eat 3,000 tiny insects in just one night!
Pipistrelles are the most common and widespread of all British bat species. There are two very similar species, the Common Pipistrelle and Soprano Pipistrelle. Common Pipistrelles are abundant in the Bailiwick and Soprano are only known from a few autumn records in Alderney. Pipistrelles are the bats that you are most likely to see. They appear fast and jerky in flight as they dodge around pursuing small insects which they catch and eat on the wing.
Common Pipistrelles feed in a wide range of habitats comprising woodland, hedgerows, grassland, farmland and urban areas. They generally emerge from their roost around 20 minutes after sunset and fly 2-10m above ground level searching for their insect prey. They feed mainly on a wide range of small flies as well as the aquatic midges and mosquitos. This species roosts in tree holes and crevices but also in bat boxes.
Grey Long-eared Bat (Plecotus austriacus)
In the UK, Grey Long-eared Bats are very rare bats found only in a few places in southern England. However in the Bailiwick, Grey Long-eared Bats are the most common and widespread the long-eared bat species on the islands.
It can be very difficult to distinguish the Grey Long-eared from the Brown Long-eared. The most reliable distinguishing features between them are dorsal hair colour, the length of the thumb, the ratio of the length of the thumb to the length of the forearm, the width of the tragus, and face colour (pinkish- brown in the Brown Long-eared) and shape (Grey Long-eared have a longer and darker muzzle).
A Grey Long-eared Bat’s ears are nearly as long as their body but are not always obvious; when at rest they curl their ears back like ram’s horns or tuck them away completely under their wings leaving only the pointed inner lobe of the ear visible. This bat is generally a little larger than the Brown Long-eared Bat, and has a dark face.
This species emerges in darkness and is a very skilful flier. They feed on moths, crane flies and small beetles. Relatively little is known about the habitat use of the Grey Long-eared Bat. Recent studies show that they tend to forage over meadows, grasslands, gardens and near forest edges, up to 6 km away from the roost. Long-eared Bats are most often found in older houses with large open roof voids which allow the bats to fly around in the roof.
Brown Long-eared Bat (Plecotus auritus)
Brown Long-eared Bats are medium sized and, like the Grey Long-eared Bats, their ears are nearly as long as their bodies but this is not always obvious as when they rest they curl their ears back like rams’ horns, or tuck them away completely under their wings leaving only the pointed inner lobe of the ear visible. Their ears provide exceptionally sensitive hearing, and it can even hear a ladybird walking on a leaf!
As well as catching insects in free flight, Brown Long-eared Bats are gleaners, often flying slowly amongst foliage, picking insects off leaves and bark. Sometimes they land on the ground to catch insects or to shift them into a controllable position in their mouth. They are even able to take insects from lighted windows. Their diet consists of moths, beetles, flies, earwigs and spiders. Their habit of flying close to the ground, or even landing to tackle prey, makes long-eared bats vulnerable to attack by predators such as cats.
Summer roosts are usually located in older buildings, barns, churches and trees. Winter roosts tend to be found in caves, tunnels and occasionally even trees and buildings.
Kuhl’s Pipistrelle (Pipistrellus kuhlii)
This species is similar to other pipistrelles but is larger and tends to be lighter and yellowish coloured. This species roosts in human structures in summer and is thought to use cliff crevices and cellars in winter. Kuhl’s Pipistrelle Bats are comfortable in both agricultural and urban habitats.
They are a very agile species, which feed on mayflies, mosquitoes, moths and other insects while in flight. It is regarded mainly as a Mediterranean species but recently has undergone an expansion of its range northwards.
In the UK, they are considered a migrant species rather than a resident species as they are not currently recorded as a breeding species.
In the Bailiwick, they are likely a common resident and breeder. Social calls were recorded throughout the season – these are easily identifiable. Echolocation calls can be confused with Nathusius’ Pipistrelle but social calls of the latter were only recorded in September and October indicating that Kuhl’s Pipistrelle is most likely a resident breeding species and Nathusius’ Pipistrelle is a migrant and winter visitor.
Nathusius' Pipistrelle (Pipistrellus nathusii)
Nathusius’ Pipistrelle is similar in appearance to, but slightly larger than, the Common Pipistrelle.
Nathusius’ Pipistrelles are often recorded roosting in crevices and have been found in cracks in walls, fissures in rocks and tree hollows. They feed on medium-sized flying insects such as aquatic flies, midges, mosquitoes and caddis flies.
At present, the biggest threat to the species would appear to be reduction in insect prey due to degradation of water quality, loss of foraging habitat such as woodland, treelines and hedgerows plus loss of roosting habitat.
Soprano Pipistrelle (Pipistrellus pygmaeus)
The Common and Soprano Pipistrelle were only identified as separate species in the 1990s. The two species look very similar but Soprano Pipistrelle bats are distinguished by their higher frequency echolocation call.
Soprano pipistrelles usually feed in wetland habitats and also around woodland edge, tree lines or hedgerows, and in suburban gardens and parks. They generally emerge from their roost around 20 minutes after sunset and fly 2-10m above ground level searching for their insect prey, which they catch and eat on the wing by ‘aerial hawking’. They feed mainly on small flies, particularly midges and mosquitoes that are associated with water.
Soprano Pipistrelles appear to be more selective in their habitat use than the more generalist Common Pipistrelle. Summer roosts are usually found in crevices around the outside of often newer buildings. This species also roosts in tree holes and crevices, and also in bat boxes.
Whilst there are previous records of Soprano Pipistrelle from Alderney, the ten recordings over three nights in June 2022 (22nd, 23rd and 26th June) are the first records of Soprano Pipistrelle for the project. They are all from the same location in a residential area in the southern edge of St Annes. The timing of the records suggests that Soprano Pipistrelle could be a resident species on Alderney.
Greater Horseshoe Bat (Rhinolophus ferrumequinum)
The Horseshoe Bats can be distinguished from other British bats by the presence of a complex horseshoe-shaped nose leaf which is related to their particular type of echolocation system. The Greater Horseshoe Bat is the largest European Horseshoe Bat.
Greater Horseshoe Bats emerge from their roosts within half an hour of sunset. Between May and August they usually return to their roosts after about an hour and remain there until their second feed around dawn. However, from late August they may remain away all night.
Greater Horseshoe Bats feed mainly by low flying hunting and insects are taken in flight or occasionally from the ground. They often behave like flycatchers, ‘watching’ from a regular perch and flying out to take passing insects and large prey is taken to a regular feeding perch. Their diet consists of chafers, noctuid moths, craneflies and caddis flies.
Greater Horseshoes Bats were originally cave dwellers, but few now use caves in summer – most breeding females use buildings, choosing sites with large entrance holes with access to open roof spaces warmed by the sun. In winter the Greater Horseshoe Bat uses caves, cellars and tunnels as hibernation sites. When roosting they hang free with the wings more or less enfolding their body.
The decline of this species may be due to factors such as disturbance of roosts and intensive agricultural practices including loss of permanent pasture. These bats are particularly sensitive to disturbance at their nursery and winter roosts.
Lesser Horseshoe Bat (Rhinolophus hipposideros)
The Lesser Horseshoe Bat is one of the smallest British species. Like the Greater Horseshoe Bat, it has a complex nose leaf which is related to its particular type of echolocation system. At rest it hangs with its wings completely wrapped around the body, differing from the Greater Horseshoe Bat whose face can usually be seen.
In the summer Lesser Horseshoe Bats emerge about half an hour after sunset. The emergence follows a period when the bats fly around within the roost with some appearing outside the roost entrance. They are particularly sensitive to disturbance and twist their bodies as they scan their surroundings before flying off.
Their diet consists of flies (mainly midges), small moths, caddis flies, lacewings, beetles, small wasps and spiders. They feed amongst vegetation in sheltered lowland valleys and rarely fly more than five metres above the ground, frequently circling over favoured areas and often gleaning their prey from branches. Large prey is often taken back to a temporary night roost or sometimes dealt with whilst the bat is hanging in trees.
Like Greater Horseshoe Bats, they were originally cave dwellers, but summer colonies are now usually found in the roofs of larger rural houses and stable blocks offering a range of roof spaces and a nearby cellar, cave or tunnel. The colony may shift between attics, cellars and chimneys throughout the summer, depending on the weather.
The Lesser Horseshoe Bat is rare in the British Isles and is currently only found in Wales, western England and western Ireland. Their is attributable to several factors, including disturbance to roosts and intensive agricultural practices. Sensitive management of their foraging habitats is very important.
Serotine (Eptesicus serotinus)
The Serotine is one of Britain’s largest bat species and is usually one of the first to appear in the evening, often emerging in good light. They have broad wings with a slow, highly manoeuvrable flight with occasional short glides or steep descents, flying close to vegetation and amongst tree canopies.
Their diet consists of flies, moths and beetles which they catch in flight or by plucking them from the ground or vegetation. Serotines are also known to feed near lamp posts, where moths have been attracted to the light, and even catch prey from the ground.
Serotines have dark brown fur and a dark brown or black face, wings and ears. The fur is a paler yellow-brown on the underside and the ears are large and pointed. Juveniles have darker fur than adults.
Serotines roost mainly in buildings with high gables and cavity walls. They can be found in older buildings and church but are less often found in modern buildings. They are one of the most building-orientated species and are hardly ever found in trees.
Serotine Bat is one of the less common species in Britain. This decline in numbers is probably due to loss of feeding habitat where large insects can be found. As they roost mostly in buildings, they are subject to the effects of building work and the use of toxic chemicals in timber treatment.
Noctule (Nyctalus noctule)
The Noctule Bat is one of the largest British species and is usually the first bat to appear in the evening, sometimes even before sunset, and head straight toward foraging areas. Noctules have a characteristic powerful, direct flight on narrow pointed wings. They are high flyers, flying well above the tree canopy and use their powerful flight to repeatedly dive in the sky as they hunt their insect prey. They catch most of their prey on the wing which is eaten in flight, but occasionally insects are taken from the ground. The Noctule’s diet consists of moths, winged ants, midges and flying beetles. During spring they feed mainly on smaller insects such as midges, changing their diet to take beetles and moths later in the season.
Noctule Bats are a woodland species, living primarily in tree holes and very rarely in buildings and bat boxes.
While the Noctule Bat is widespread in the UK, it is thought the population may have declined following the introduction of intensive farming methods. It is also vulnerable to the loss of mature trees, which it uses as nesting and hibernation sites.
Leisler's Bat (Nyctalus leisleri)
The Leisler’s Bat is similar to the Noctule, but smaller with longer fur, particularly around the shoulders and upper back, giving it a lion’s mane appearance. It was formally known as the hairy-armed bat! Its fur is golden-tipped or reddish-brown, which is darker at the base.
Leisler’s Bats appear early in the evening, soon after the Noctule. They usually fly high and fast with shallow dives in the open near the treetops, however you might also see it flying around lamp posts looking for insects attracted to the light. They forage for flies, moths, caddis flies and beetles, with their diet varying greatly according to their habitat.
Leisler’s Bat is naturally a forest and woodland species, roosting in tree holes however in some areas, bat boxes have proved to be a useful substitute for natural roost sites. They are an adaptable species and can be found in mixed rural and residential areas. They also roost in buildings, both old and new. They hibernate in tree holes, cracks and cavities of buildings and occasionally in caves and tunnels.
Natterer’s Bat (Myotis nattereri)
Natterer’s Bat is a medium-sized species. They have narrow ears which are fairly long and slightly curved backwards at the tip. A characteristic feature of this species is a fringe of very stiff bristles along the trailing edge of its broad tail membrane. This species of bat used to be known as ‘red-armed bat’ which is because of its pinkish limbs.
Natterer’s Bats have a slow to medium flight, sometimes over water, but more often amongst trees, where their broad wings enable them to have great manoeuvrability at slow speed. They normally fly at heights of less than 5m, but occasionally may reach 15m in the tree canopy. Much of the prey is taken from foliage and includes many flightless or day-flying insects for example they sometimes snatch spiders from their webs. Sometimes larger prey is taken to a feeding perch. They feed on flies, small moths, caddis flies, lacewings, beetles, small wasps and spiders.
Most known summer colonies roost in old stone buildings with large timber beams or large old timbered barns. Crevices in beams or gaps in beam joints are also common roost sites.
Whiskered Bat (Myotis mystacinus)
Brandt’s Bat (Myotis brandtii)
Whiskered Bat is very similar to Brandt’s Bat and the two species were only separated in 1970. Both are small species with somewhat shaggy fur. Brandt’s Bat is slightly larger than Whiskered Bat. The two species are most reliably separated by differences in their teeth. Other distinguishing features are thought to include their tragus and claw length.
These two species roost in all kinds of houses, old or modern, and may use bat boxes. They will often roost together, but in separate colonies.
The species’ are typical of open country, parks, gardens and frequently forage along a familiar route like a hedgerow or woodland edge. They will emerge within half an hour or sunset and remain active throughout much of the night. They have a fast and fluttering flight which is generally level with occasional swoops. Their diet consists of moths and other small insects and spiders. Studies have indicated that whiskered bats have more flexible foraging.
Whiskered Bat is thought to be slightly more common and widespread in the UK than Brandt’s Bat. They are vulnerable to the effects of modern agricultural practices and decline of woodland, which result in loss of suitable feeding habitats and hollow trees for roosting.
Either Whiskered or Brandt’s Bat would be a new species for Guernsey. At the current time, there are no good clear criteria for distinguishing Whiskered and Brandt’s Bat acoustically with confidence. In Alderney, there is a single previous record of Whiskered, Brandt’s or Alcathoe Bat. In 2021, we assigned eight recordings to Whiskered or Brandt’s Bat. Four of these recordings were from Alderney. The remaining six recordings were from the south-east corner in Guernsey.