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Bats in my Loft!

When I moved into my new house, I went up into the loft space to store some of my boxes. On a piece of wood in one corner were lots of droppings. I knew straight away that they were bat droppings. They are very distinct in size and consistency and their distribution in this one area very much suggested bats were using my loft to roost at some point.

Bat droppings most commonly accumulate underneath the roost area, and below the points bats use to access a building or a roosting area. I could see, on the outside of the house, where some droppings also were accumulating on a small ledge. All UK bats feed on insects, so their droppings are made up of dried insect remains. They crumble easily as there is no moisture in them. A mouse dropping looks similar, but they have a lot of moisture so do not crumble.

I was very excited to discover this, so set a trail cam up, facing the space. I was delighted to capture a brief clip confirming that at least one bat was using the space! This clip shows the brief clip in normal speed and then slowed right down.

To gauge how regularly this space was being used, I cleared the area and place a new board there to catch the droppings. At no point, when I went up in the loft , did I ever see a bat. I think it may be roosting up behind the insulation board. Within a week, there were a lot of droppings back on the board.

I tweeted about my excitement online. There are several different bat species recorded in the area and I wondered what species this was. I could not tell from my video footage. I was delighted when I received a comment from Dr Tom Etheridge from EcotypeGenetics.

Tom offered to test the droppings and then tell me what species of bat I had. Ecotype Genetics have a highly optimised panel of genetics tests that are species-specific, enabling them to detect the presence of DNA from any of the 18 species of bat that live in the UK, distinguishing between closely related species and importantly, their tests can identify the presence of multiple bat species from one collection of droppings with their 'mixed species' analysis. Many bat roosts are used by multiple species across a year, and in order for ecologists to make an informed assessment of the importance of a roost and to provide the information required for license applications, it can be critical to identify all species present - not just the most abundant ones. This mixed species analysis can also often lead to the discovery of rare species roosting with a more common one - for example, grey long-eared bats, one of the UK's rarest bats, can be found cohabiting with brown long-eared bats - but distinguishing them visually can be very tricky.

Tom sent me some small vials and gloves to use so I did not contaminate the samples in any way. I carefully collected the droppings, packaged them up and sent them off to the EcotypeGenetics lab.

The company provide genetic solutions to ecologists and conservation groups across the UK to support protected species surveys, monitoring programs, and conservation projects. One of their specialisms is providing DNA-based species identification of bats from a range of ecological samples, including droppings! This type of genetic testing has become a valuable tool used by ecologists in their efforts to ensure the conservation of UK bats, as it provides a reliable method for non-invasively identifying the presence of each species at a site of interest. Although my fascination was only on a personal level, I can see why this method of ID'ing could be incredible for anyone studying a site and wanting to know for sure, which species have been present.

After a week or so, Tom contacted me. After extracting DNA from 5 tubes of droppings, they tested for the presence of all the UK's bats and found that there was one species present - Pipistrellus pygmaeus - The Soprano pipistrelle bat. This species is slightly smaller than the common pipistrelle and they were only identified as separate species in 1999.

(image from

I would like to thank Tom and EcotypeGenetics for doing this test for me. I will keep an eye out in the loft and will be setting the trail cam to see if I can capture any more footage.


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