We're listening for bats at the moment, to see if there's any here. Bats echolocate,
they shout very high-pitched sounds. The best way of thinking about it is, at night when
it's dark, we use a torch of light. So it's a sort of light our way. They use a torch
of sound if you like. So they shout out these high-pitched sounds, which either go off into
the distance, never to hit anything, or some of them will hit an object like a tree or a wall
or ideally an insect, which is what they're using the sound for. And that will create an echo. The
sound will bounce back to the bats ears, which you'll be listening for. It's got its own particular
frequency. Each bat has its default frequency, if you like, or they can change it. And we are
listening for those sounds. Now the bat detector, or we should really give it its proper name,
it's an ultrasound detector, detects ultrasound. So it picks up all sorts of things. So that
keys, I don't know if you can get that, but you get all sorts of noise, which is above the human
hearing range normally. But what we're really listening to is, I've got it tuned in at 45
kilohertz at the moment, so that we're listening for the most common British bat, which is the
common pipistrel, which really is found all over the country, but particularly greater Manchester.
We've got loads and loads of batteries to cross greater Manchester as a whole, where pipistrels
live. And so we've got the bat detector tuned in for those. What it's actually doing is transferring
the sounds down from something ultrasonic to something within the human hearing range,
so that we can listen to the sounds that they make. We can hear what they're doing. We can understand
when they're feeding, when they're flying faster, when they're slowing down, when they're twisting
and turning in their normal fluttery flight. And we can tell whether they're commuting, so moving
from one site to another, and when they're foraging catching insects. So really quite a useful tool.
The sounds that they make are different to each species of bat. So the common pipistrel
echolocates at 45 kilohertz. The soprano has got a higher voice. It echolocates at 55 kilohertz.
And then you've got other bats which are around about 45, but they sound different. So there's
different mechanisms that we can employ to determine what species have we got. As well as
doing the bat work this evening, I have an interest because we're doing a survey as a bat group of
greater Manchester as a whole. We want to understand what bats are here, but particularly within the
town centres and city centres in Manchester. So the records that we collect tonight are really
quite interesting. Even if we don't get many records, that's still very important because it shows
where bats aren't using, as well as where they are using. So we can put more energy into either
improving those bits where they aren't, or where they aren't their bats rather, or where we're trying to
enhance those areas where there are bats.
