Echolocation
Unlike other species in this family, long-eared bats echolocate through their noses. Echolocation calls range from 25 to 50 kHz, peaking at 35 kHz. They are so quiet they can only be heard as ‘ticks’ through a detector from two to three metres away, so are often known as ‘whispering bats’.
Habits
This is a woodland bat. It prefers to forage in open deciduous woodland, parkland, and large gardens and trees in towns and cities. Beetles, flies, earwigs and spiders are taken, but moths are a particularly important part of their diet. As many moths can hear the ultrasound of bats, the ability to approach prey silently is important.
Summer roosts are usually in trees or older buildings; churches, barns and old houses with large roof voids that are close to trees so the bats can avoid crossing open spaces when they leave the roost. They are very faithful to their roosts, and usually arrive in summer roosts earlier and stay later into the year than other species. As they leave to feed, they disperse along regular routes, flying close to vegetation. Usually they feed within 500 m of the roost, and never further than three kilometres. Large prey are taken to a night roost or regular feeding perch such as a porch or barn, sometimes identifiable by piles of discarded moth wings. In winter they hibernate in tree holes, caves, tunnels and deneholes preferring very cold sites.
Reproduction and life cycle
Nursery roosts are usually composed of 10 to 50 bats. Unlike some species, males are often present. One young is born around late June to mid-July and weaned at six weeks.
Small numbers are found at underground swarming sites in autumn. Bats of this species are known to have lived up to 30 years.
Distribution, status and conservation
After the pipistrelles, this is probably the most abundant bat in the UK. Prior to 2008, records in Kent were mainly of roosts in buildings where this species’ droppings are very obvious, along with bats seen in hibernation and grounded bats. Their habit of flying close to the ground makes them very vulnerable to cat predation. The low intensity of their calls explains the absence of historic detector records. The BCT Bechstein’s Bat Survey in Kent 2008/9, using an acoustic lure to trap bats in cluttered woodland, led to many new records. This was the species most frequently captured in woodland, both in Kent and other counties involved in this survey, highlighting their under-recording in most surveys. Modern full-spectrum detectors now record brown long-eared more often.
The species appears to have undergone a major decline during the twentieth century. Although NBMP data suggests show a long-term stability with possible mild increase, evidence in Kent of the species’ past presence (in the form of old droppings) has been found in many buildings where bats no longer appear to be present, or are only present in small numbers. KBG believes there is still cause for concern in Kent, where the over-management of woodlands and the conversion of old farm buildings such as oast houses and barns has contributed to their loss by reducing suitable roosting and feeding sites.
