PETER FROST discovers an amazing nature detective story in the silent night-time world of bats.
There are eighteen species of bat in Britain and the number of those species is increasing. Today seventeen kinds of bat are breeding here but one very rare species the greater mouse-eared bat is down to a population of a single male so when that animal dies the species will be gone from our shores.
Other bat species are choosing to make their home here as climate change kicks in. Visitors from more southern climbs are coming to our shores and discovering the weather and conditions here suit them. They stay and breed.
Before we start let’s get some well known and widely believed bat myths out of the way. British bats don’t suck blood. Nor do bats fly into your hair and get tangled in so they have to be cut out.
Even in Transylvania bats don’t really suck virgin’s blood. There are vampire bats but they are tiny, about the size of your thumb, and live only in Mexico, Central and South America.
Sadly these colourful myths have given bats a bad name and many people are still frightened by the swooping silent flight of bats hawking for small insects at twilight.
Outside our favourite country pub on a warm evening it’s almost as much fun watching the drinker’s reactions as it is to watch the bats flitting in and out of the pubs floodlights.
Let’s get back to science. Bats are mammals and the wide range of bat species means that these flying animals account for almost a quarter of our mammalian species.
Sadly, overall bat populations have suffered severe declines during the past century. Insecticides have affected their diets and residues build up in the animals themselves.
Roosts have disappeared in old buildings and rotten trees as we tidy up our woodland or convert or demolish ancient buildings.
Bats are protected by law but that doesn’t mean unscrupulous property developers aren’t averse to putting profit before bat conservation.
There is some good news. It is easier than ever to study these amazing creatures. Modern electronic bat detectors make spotting and identifying bats much easier than it once was.
Local bat groups, local nature organisations and country parks often organise public bat evening events where you can look and listen to the bats hunting their prey in the twilight.
Bat experts are usually on hand to explain the bat’s life cycle and identify the many species.
As the public and particularly future generations get more knowledgeable about bats so we can expect them to be more sympathetic and protective to them.
The common pipistrelle (Pipistrellus pipistrellus) is the most common bat species in the British Isles.
Weighing around 5 grams (less than a £1 coin). A single pipistrelle can eat 3,000 tiny insects in just one night.
Pipistrelles are common in woodland and farmland but is also found in cities and towns where it roost in lofts and buildings.
As late as 1999 what was thought to be a single species, the common pipistrelle, was split into two species by some remarkable detective work by bat researchers.
Using those newly developed bat detectors the bat detectives realised that two groups of pipistrelle bat had distinctively different voices. I was the first time in nature that a species was defined by its call.
The common pipistrelle uses an echolocation call of 45 kHz, while the new species named the soprano pipistrelle echolocates at 55 kHz.
other differences, in appearance, habitat and food, have also been observed.
Hearing is important to all bats but one British species, the Brown long-eared bat’s huge ears provide even more sensitive hearing experiments have determined it can hear a ladybird walking up a twig.
This article first published in the Morning Star, 2013