An introduction to UK bats

Daubenton;s Bat, myotis daubentoni, adult, flying over water - Dale Sutton/2020vision

June is a great time of year to look out for bats - and it makes a super 30 Days Wild activity! Our Volunteer Communities and Wildlife Officer Megan gives us the lowdown on these marvellous mammals.

As one of my activities for 30 days wild this June, I took a trip to Priory Country Park in Bedford just before sunset, armed with a bat detector to see what I could find. After a lovely walk around the lake admiring the sunset and the full moon that evening, the bats started to emerge, and there was more than I had ever hoped for. There was an abundance of bats flying around my head, swooping through the trees and over the lake, and my bat detector immediately started to pick them up, showing me there were many different species flying around including common and soprano pipistrelles, as well as noctule bats. This time of year is a great time to look for bats, and so I thought I would share a bit of information surrounding them, and how you might be able to find out which bats are flying over your head.

An introduction to bats in the UK:

Because bats possess hairs on their bodies and are warm blooded, they are mammals, just like us. They are also the only mammal that can fly, with their wings showing a pentadactyl (literally: limb with five digits) limb structure, which is the same as human hands.

In the UK we have 18 different species of bat, with 17 being known to breed. The most common you are likely find are the common and soprano pipistrelles, which are our smallest bats, with a wingspan of around 20cm. Their bodies are about the same size as your thumb,  and would feel the same weight as holding about 10 paper clips (4-7g). Our largest bat is the noctule, which I mentioned earlier, with a wingspan of around 40cm, but even these can still fit in your hand!

A pipistrelle bat being held

A pipstrelle bat being held for surveying by Amy Lewis

What do bats eat?

The main diet of bats in the UK mainly consists of lots of insects; which explains why they were so attracted to the lake and trees surrounding Priory, as this would have provided a feast for them. Being nocturnal, the most active time for bats is at dusk, and for a couple of hours after sunset, when they start to emerge from their roosts to look for food (these roosts will be places like hollow trees or even in roofs of buildings). Flying around so much uses a lot of energy, and so they have to make up for this energy loss by eating more, meaning one bat can eat up to 3,000 insects in one night!

How do they fly at night?

Having to fly around in the dark avoiding trees and eating insects may sound a little tricky to us, so how do bats do it? Well, they are highly adapted for living this nocturnal life, and at night their ears are much more important than their eyes. Bats use echolocation to dodge objects and find the insects they would like to eat. They essentially posses their own unique radar system, and as they fly around they will produce ultrasonic ‘sounds’, which produce a returning echo that they use to give them information on the size and shape of the object ahead of them.

We are mostly not able to hear these calls, and this is when bat detectors can help us. These detectors will convert the calls into frequencies we can hear, and from this you can determine what species of bat is calling, as different species produce different frequencies and calls.

Child with bat detector by Emma Bradshaw from WildNet

Child with bat detector by Emma Bradshaw

A year in the life of a bat

At around this time of the year, in June, female bats should be starting to give birth to their young. They usually give birth to a single pup, which they will then suckle for around six weeks before the pups are capable of catching their own insects. However you may find pups on the floor after around three weeks, as they try to learn how to fly.

A bat’s mating season actually occurs in Autumn, and then the females will delay the birth until after their hibernation and the weather gets warmer. This hibernation occurs over the cold winter months, when there are less insects to eat. They will slow down their metabolic rate and lower their body temperature to conserve energy, and find a nice quiet place to sleep through the winter. However, you may see them flying about on warmer nights if they are running low on energy and need to stock up on insects.

Helping bats

Our bats are protected by law in the UK, and it is illegal to harm or destroy a bat roost. If you find an injured bat, or one lying on the floor, it is best to call a bat helpline to find out what best to do (the National Bat Helpline, run by the Bat Conservation Trust, is a good place to start). If you do have to move one out of the way of danger, make sure to wear gloves and try not to handle it too much. If you think you have some roosting in your house: don’t panic. Bats are gentle creatures and are not pests so they will not cause any damage.

I often feel as though bats get a bit of a bad reputation, but they are lovely animals and it is important we care for them just as much as any other species. It was a privilege to be able to watch so many flying around Priory Country Park, and I hope this has inspired you to do the same where you live.