We're waiting for the light to go. We're standing in the woods in

Sidonam in South London by a pond surrounded by trees. There's lots of bird songs still and it's getting dark.

We've just put our head torches on and we're waiting for the bats to appear.

Hopefully we should see some soon. It's quite a chilly night but because they've

just woken up from hibernation we're hoping that they'll be desperate for food.

Yes let's hope they don't decide it's too cold to come out and they'd rather stay inside that old railway

tunnel where they all seem to be.

I'm Caroline Bailey and for this edition of the documentary on the BBC World Service

I'm looking for bats in the woods in suburban London.

Depicted in some cultures as terrifying blood-sucking vampires and devil-like creatures,

they can evoke both fear and revulsion.

A fear exacerbated by the havoc of COVID-19 and a blame game linking bats to the

source of the pandemic. But what is it about bats? Farmers, environmentalists and

scientists love them.

Should we love them too?

My guide on this dark night is Bat expert Ella Browning,

a PhD student at University College London.

Bats in the UK are constantly emitting sound as they fly around and they do this to navigate

and hunt down their food so we can use those calls to track where they are.

And for some species, we're able to actually ID them

from the echolocation cause, so we can monitor certain species

in certain locations.

...