The Brown Long-Eared bat is also known as the “whispering bat”. This is because it uses quiet echolocation. You can find it in the British Isles and Europe. Known for its big ears, the Brown Long-Eared Bat has a charming look, despite being shy. It is smaller than its cousin, the Gry Long-Eared bat, but more common.
| Scientific Name | Plecotus auritus |
| Length | 3.7cm – 5.2cm |
| Wingspan | 25cm – 30cm |
| Weight | 6g – 12g |
| Colour | Brown-grey fur on the back and ple underneath |
| Habitat | Woodland, edge habitats, parklands, urban areas, wetlands |
| Diet | Moths, midges, flies, beetles |
What Do Brown Long-Eared Bats Look Like?
With ears almost as long as its body, this bat stands out. The body length averages 3.7-5.2 cm (1.5-2.0 in) with a wingspan ranging from 25-30 cm (9.8-11.8 in). They weigh between 6-12 grams (0.2-0.4 oz). They have soft, fluffy fur which is brown-grey on the back and pale underneath.
The Brown Long-Eared bat curls its long ears back when resting or hibernating. like ram’s horns.
What Does Their Echolocation Sound Like?
Unlike most types of bat, the Brown Long-Eared bat echolocates at quiet frequencies. Often below 35kHz.
Due to this, they are sometimes called “whispering bats”. Bat detectors can usually pick up faint calls. That said, because they are quiet, these bats may be harder to detect than more vocal species.
Where Do They Live?
The Brown Long-Eared bat lives throughout Europe and parts of Asia, including Russia. They are also found in parts of North Africa. In the UK, they’re widespread. They’re more common in England and Wales than in Scotland or Northern Ireland.
Roosting Sites
In the summer, they like to roost in old buildings, barns, and lofts. They especially like places with stable temperatures, necessary for raising their offspring. Maternity colonies are often found in these roosts. Bats usually stay near the roof. They either hang or squeeze into small spaces.
During winter, bats look for colder and more humid places to hibernate. People prefer caves, mines, and cellars because they stay stable and cool. The bats often tuck themselves into crevices or hang from the roof during this period.
Preferred Habitats
These bats live in a range of habits which include;
- Woodlands: These habitats have lots of bugs for food and places for bats to rest, like tree holes or loose bark. The intricate structure of woodlands offers varied hunting grounds.
- Edge Habitats: The edges where habitats meet, like between a woodland and a meadow or a forest and a wetland, have lots of insects. These edge habitats are often frequented by this bat for foraging.
- Parks and Gardens: In urban areas, these bats search for food in big gardens, orchards, and parks with many trees and plants.
- Wetlands: Wetland areas attract bats because they have lots of insects. This happens more often when wetlands are next to woodlands or other places that bats like.
What Do Brown Long-Eared Bats Eat?
Their diet consists of:
- Moths
- Spiders
- Beetles
- Small flies
Hunting Strategy
These bats don’t catch insects while flying like other bats. They have a unique way of catching insects called “Gleaning”.
Gleaning involves catching prey from surfaces such as leaves, bark, or the ground. They are adept at hovering in front of a surface, like a leaf, and plucking insects off with precision. This method is very efficient and allows them to exploit a niche that many other bats do not.
They usually forage alone. However, sometimes they forage in groups when there’s lots of food. This might be opportunistic behaviour rather than a coordinated group effort.
Despite their quiet echolocation, Brown Long-Eared bats are highly efficient hunters. They’re capable of catching prey directly from surfaces or in flight.
How Do They Breed?
The mating season begins in late summer and extends into early autumn. From August to October. Timing can vary depending on location and environmental conditions of the year.
Swarming Behaviour
One of the prominent features of their mating period is their swarming behaviour. Males and females gather, often near underground places such as caves, tunnels, or mine shafts. Bats swarm to find mates, meeting many partners to choose from.
Mating Calls and Displays
During the mating season, male bats make distinctive calls to attract females. These calls can be longer, louder, and more complicated than their usual echolocation. Males might also perform aerial displays to attract or compete for mates.
Delayed Fertilization
After mating, the female stores the male’s sperm in her reproductive tract all winter. It is only in the spring, after hibernation ends, that fertilization occurs. This means pregnancy and raising pups happen during the warmer months when food is more available.
Maternity Roosts
After fertilization, females create groups in late spring and early summer. They gather in specific locations, like tree hollows or attics, to give birth and rear their young. Maternity colonies provide safety and a good environment for the pups to grow.
Birth and Development
They give birth to one pup, though twins are possible but less common. The pup is born hairless and with closed eyes, relying entirely on its mother’s milk in the initial weeks. Within a month, the young bat will be flying and hunting on its own.
When and Where Do They Hibernate?
They hibernate in the colder months of the year when insect prey is scarce. This is often in late October to November. They start emerging when temperatures start to rise and food is more available. Often in late March to April.
Choosing Hibernation Sites
They prefer hibernation sites that offer consistent, cold temperatures. It is important to have stable conditions. Frequent temperature changes can wake bats up too early and waste their energy.
They often choose caves, mines, tunnels, or cellars for hibernation. These places have stable conditions and high humidity so they don’t dehydrate. They also provide protection from predators and external disturbances.
Physiological Changes During Hibernation
During hibernation, bats reduce their metabolic rate. Their heart rate drops from about 200-300 beats per minute when active to as few as 10 beats per minute.
Their body temperature also decreases. It can drop very near the ambient temperature of the hibernation site. Often hovering just above freezing point.
Bats store fat before hibernation to survive the winter. These reserves are slowly used up as they hibernate. Like many other bat species, it may lose up to a quarter of its body weight during hibernation.
Periodic Arousals
Even during hibernation, bats will sometimes wake up or experience “arousals“.
During these arousals, they may;
- Move to a different spot within their hibernation site
- Drink water, or
- Even venture outside for a brief moment
After a short period, they return to their hibernating state.
The exact reason for these arousals is not fully understood. However, they play a crucial role in the bat’s survival. Even though they consume a significant amount of the bat’s fat reserves.
Emergence from Hibernation
As spring approaches and temperatures start to rise, they emerge out of hibernation. This awakening is a vulnerable time, as their fat reserves are almost all gone. They need to feed and replenish their energy as fast as possible. The resurgence of insects in warmer weather provides them with the necessary food.
Threats to Brown Long-Eared Bats
This species faces a range of threats that impact its survival. These include:
Loss of Habitat
They often use buildings like barns and old buildings, for roosting. Demolishing, renovating, or repurposing buildings destroy roosting sites.
Farming and urban development cause a loss of habitats like hedgerows and woodlands.
Pesticides and Chemical Pollutants
Insecticides can reduce insect populations, depriving bats of their primary food source.
Also, bats can consume toxins by eating insects that have been exposed to pesticides. This can affect their health and reproductive capabilities.
Light Pollution
Bats are sensitive to artificial lighting.
Lighting near roost sites can disturb bats so they abandon them. It can also disrupt their foraging patterns, and make them more visible to predators.
Disturbance During Hibernation
Disturbances, whether from humans or predators during hibernation can be fatal.
Waking up from hibernation uses a huge amount of energy, depleting a bat’s fat reserves. Repeated disturbances can lead to bats running out of energy and dying before the winter is over.
Disease
White-Nose Syndrome has devastated bat populations in North America. It poses a potential threat if introduced in Europe.
Other diseases can also impact populations, especially when combined with other stressors.
Climate Change
Altered weather patterns can influence insect availability. This could lead to reduced food sources during crucial periods.
Shifts in temperature can also affect when, and for how long bats hibernate. As well as the suitability of hibernation sites.
Wind Turbines
There’s growing concern about bats colliding with wind turbines. Bats can suffer from;
- Barotrauma and
- Internal injuries caused by sudden pressure changes near moving turbine blades.
Public Misconceptions
People sometimes hurt or destroy bat roosts because they don’t understand or are afraid of bats. Public education is essential to dispel myths and promote conservation efforts.
Conservation Status
The IUCN Red List classifies the Brown Long-Eared Bat as a species of Least Concern.
This designation is because of its wide distribution and large population. As such, it is unlikely to be declining fast enough to qualify for a more threatened category.
That said, it’s essential to interpret “Least Concern” correctly. It doesn’t mean the species isn’t facing threats or conservation measures aren’t needed. It means that, from a global perspective, it is not currently at immediate risk of extinction.
It is protected under various national and international legislations. This reflects the recognition of the challenges it faces.
On a more local scale, populations can vary in their stability. In some areas, it might be under more significant threat due to;
- Habitat loss
- Human disturbance, and
- Other factors
Local conservation statuses might differ. Ongoing monitoring and conservation measures remain critical to ensure their continued survival.
When and Where to See Them
You can see Brown Long-Eared bats throughout the UK, with the exception of some Scottish isles.
They are most active from May to September. Around dusk, take a stroll in wooded areas, parks, or gardens. If you’re lucky, you might witness their graceful flight and delicate hunting techniques.