Last year, on a bit of a whim, I bought my husband a bat detector. I can’t remember whether it was for birthday or Christmas but it’s immaterial as both are in December when bats are snoozing the winter away in their ‘bat caves’ or wherever they choose to live. I think I was partly inspired by our Spring holiday in the Forest of Dean when we’d stayed in an incredibly ancient old house, possibly one of the oldest still inhabited houses in England (the foundation stones in the basement were rumoured to be Roman) and we were lucky enough to observe bats flying in and out of the barn opposite every evening. These were greater horseshoe bats, a rarity these days and high on the list of protected species. As a result, part of Dean Hall is declared a SSSI (Site of Special Scientific Interest).
We do see bats in our own garden. It’s usually the height of summer and we see them swooping across our pond to catch insects. Their movement is so different to birds that often it just catches our eye. However, we had been wondering what variety of bats were around and I thought the bat detector would be one way of finding out.
For those of you not familiar with such a device, a bat detector is tuned, a bit like a radio, to pick up different frequencies. So it is listening for the echo-location calls of the bats. It clicks away at you once it’s heard a bat and then, depending on the frequency of the reading, you can then cross-check to identify the species of bat. (For more about bat detectors, take a look at the Bat Conservation Trust). This all sounds very good until you try it out and get used to it We picked a warm summer’s evening in June to stand in the garden at dusk. It felt like the ideal night for bats to be flying but we waited, twiddled the dials a bit, but nothing happened. John gave up and wandered off down the garden, handing the device to me. I wasn’t sure what to do next but suddenly it started clicking in my hand. I was so surprised that I nearly dropped it! Sure enough, as we looked up at the clear evening sky, there they were flying around. We seemed to be getting a reading around 45-50 khz which implied they were common pipistrelles. Of course when you’re new to something, you inevitably give yourself doubts and so we decided to look out for local bat walks so that we could head out with an expert and find out if we were doing this bat detection thing correctly.
I registered for a walk with the Friends of Bushy Park but it was full so I was put on the waiting list. Then another walk was advertised in our local Hatherop Park in Hampton so I signed up for that. Of course the inevitable happened and places became available on the Bushy walk as well so we went out two nights in a row on a walk with the same expert from the London Bat Trust.
The two walks were quite contrasting. The first was on Thursday 31st August which happened to be one of those unseasonably cold evenings. We met at dusk at the Teddington Gate and walked down Chestnut Avenue to the Heron pond. We had never been in the park that late before and certainly not after dark so it was an interesting experience all round. It was really quite dusk before the bats emerged. There is an old fallen willow tree by the Heron pond and they were particularly active around that. We certainly had lots of common pipistrelle and also soprano pipistrelle and we got to see a noctule bat skimming low over the water. Our guide was very informative, explaining that a bat as small as a common pipistrelle needs to eat between 2000 – 3000 insects per night! It was also surprising to learn that London overall has a very healthy bat population. Of the 18 species that breed in the UK, 17 are found in London and they are present in all London boroughs. They are certainly around Hounslow as a number of us witnessed them flying over St Stephen’s Church after a PCC meeting in July. I’m pretty sure you’d see them over Ss Philip & James in Whitton too, you just need to be there at the right time.
Leaving Bushy Park in the dark and trying not to unsettle any deer we passed was certainly quite strange but possibly not as strange as our second walk the following evening. Hatherop Park is an unusual space in Hampton. When you walk into the park, it looks very ‘municipal’ with it’s play area and sports grounds. However, the pathway leads into a conservation area which has recently been allowed to re-wild and there is a green corridor that connects it to Oak Avenue Nature Reserve, and it also backs on to Kempton Nature Reserve. By contrast this was a warm evening, the start of the September heatwave, and with a stunning sunset. We picked up the sight and sound of common pipistrelles again but then we embarked on a very dark walk along the ‘green corridor’ which, following all the August rain, was remarkably muddy! Our group of around 24 people carefully wound its way along the tracks, ducking to avoid hanging bramble, attempting not to be stung by unseen nettles, and not to fall over tree roots or any other hazard! It felt like some strange outdoor challenge rather than a walk in our local park and I couldn’t help wonder what the local residents thought if they saw a strange line of lights moving along the passageway making peculiar clicking noises! Did we spot many bats along the way? Sadly not! And I think after that experience, I’ll confine our bat detecting to the safer environs of our garden!
If you are interested in learning more about bats in London, do visit the website of the London Bat Group.
Outside the Backdoor 