Do you have bats using your garden?
Let us know in the comments section if you have seen bats flying over your garden taking midges, flies, beetles and moths to eat. Different species have different tastes in prey, and so their hunting methods may vary. Whatever insects they eat, flying uses a lot of energy so bats have very large appetites, Pipistrelle bats can eat as many as 3000 insects per night – good for getting rid of those biting blighters that gardens often attract, although not so good for the critters themselves.
It would be interesting to know the areas of Danygraig where they have been spotted.
Do they range widely or are they mostly found close to the woodland, field or sand dunes?
Some bats will have a range of several kilometres that they feed over.
If you haven’t seen them but would like to encourage bats to use your garden the Bat Conservation Trust has advice on gardening for bats, such as planting night-scented flowers and creating a pond. https://www.bats.org.uk/advice/gardening-for-bats
So what are bats?
Bats are mammals that can fly. In the UK there are eighteen different species of bat, seventeen of which have been confirmed as breeding here. The Bat Conservation Trust webpage has lots of information on these, with pictures, factsheets and sound files to listen to.
https://www.bats.org.uk/about-bats/what-are-bats/uk-bats.
These flying mammals locate their prey, and other objects in their surroundings, by a method known as echolocation. This is a very sophisticated system where they emit short high-frequency pulses of sound from their mouths or noses, using the returning echoes to construct a ‘sound picture’ of their environment 1. These sounds are not normally audible to humans. Bat calls can reach up to a deafening 140dB, that’s 20dB louder than a rock concert, and 15dB above the human pain threshold – most bats deal with the extreme noise of their own calls by squeezing their ear muscles shut as they squeal 3. Contrary to the common saying “blind as a bat”, they actually have very good eyesight and some species locate their prey by sight.
In the summer, female bats form colonies in trees and buildings in order to raise their babies, typically having only one infant a year; whilst in the winter they hibernate in trees, buildings or caves, emerging occasionally to eat or drink 2.
Danygraig seems to be a good area for bats. We have been doing some bat detective work in a few gardens close to the woods, using a piece of equipment called an EchoMeter Touch2 (as seen on Springwatch). This small device attaches to an iPAD making the high frequency sounds audible. It also displays the sound waves as an aid to identification. This can be complicated because the bats not only make sound for locating food, but also make ‘social’ calls, that is, they ‘talk’ to other bats, which can be at different frequencies 4.
Below are a selection of recordings (sound files) and the related sonograms/spectrogams of various species identified by the EchoMeter Touch2 in the Danygraig area. Potentially, there could be as many as nine different species using the locality, which is rather exciting. Perhaps you’d like to compare the sounds to those on the Bat Conservation Trust webpage for each of the species to see if you agree. There’s much more information on each of the species on their webpage too.
This first one is likely to be a Common Pipistrelle (Pipistrellus pipistrellus).
This second one a Soprano Pipistrelle (Pipistrellus pygmaeus) – it has a higher frequency echolocation sound.
The Pipistrelle are the commonest and most widespread British bat species, and the ones you would be most likely to see. They often emerge soon after sunset.
These echolocation sounds are at a lower frequency, and EchoMeter Touch2 suggested this was a Serotine (Eptesicus serotinus).
This is a larger bat than the Pipistrelle, one of the largest British species, particularly associated with buildings, potentially even sharing a roost site with the Pipistrelle. It also appears early in the evening and particularly likes beetles to eat during the summer (Bat Conservation Trust).
Another large bat is the Noctule (Nyctalus noctula). These live mainly in trees and usually fly in the open, a direct, fast flight, often above the trees. They are normally the first bat to appear, sometimes even before sunset. A lower frequency echolocation with a ‘chip chop’ sound.
This bat could well be a Leisler’s bat (Nyctalus leisleri).
Although similar to the Noctule bat, and flies at around the same time, it is smaller and mainly roosts in trees. Their calls are occasionally audible to humans.
There are several bats of the Myotis species that are difficult to distinguish between without an expert eye/ear or by examining them in detail. From our recordings we can say that some they are definitely Myotis, but not so certain on the actual species…unless anyone out there knows different!
The EchoMeter Touch2 identified this species as a Whiskered bat (Myotis mystacinus) – a small species with shaggy fur. Although emerging soon after sunset, they may remain active for much of the night and have a fluttering flight.
The next one was identified as a Daubenton’s bat (Myotis daubentonii), although this may be doubtful, as they are known as the ‘water bat’, scooping insects from the water’s surface with their tail or feet (Bat Conservation Trust). Saying that, I have seen bats using the pools of water on our flat roof and we do have a lot of midges…
Another two Myotisspecies identified were the Brandt’s bat (Myotis brandtii), which was only considered to be a separate species from the Whiskered bat in the 1970s, and the Bechstein’s bat (Myotis bechsteinii). The latter is considered to be a rare and elusive woodland species.
Potential Brandt’s bat echolocation recording.
A very short recording of a potential Bechstein’s echolocation calls.
There were also some recordings for Barbastelle (Barbastella barbastellus), Nathusius’ Pipistrelle (Pipistrellus nathusii) and Brown Long-eared bats (Plectus auritus) – but these may end up being social calls of other bat species and so need further investigation.
We are looking forward to more evenings of detective work, to increase our knowledge of how bats use the environment around the Danygraig estate.
1. British Bat Calls: A Guide to Species Identification. John Russ. Pelagic Publishing. 2012.
2. A Guide to British Bats AIDGAP Field Guide leaflet. Text – Field Studies Council/The Mammal Society. 2001. Second Edition.
3. NewScientist.com
4. Social Calls of the Bats of Britain and Ireland. Neil Middleton, Andrew Froud and Keith French. Pelagic Publishing. 2014.