Survey Results 2019

The Devon Bat Survey results 2019 are in!

2019 was the 4th year of the Devon Bat Survey. This large scale citizen science survey is run by Devon Greater Horseshoe Bat Project. A whopping 671 volunteers helped gather 1.4 million sound files by placing specialist bat detecting equipment in 751 locations across the county.

216 of the 695 grid squares surveyed had greater horseshoe bat activity. The levels of activity varied quite a bit between locations – at one site there were 107 greater horseshoe bat passes on a single night!

In all the detectors picked up nearly 2000 greater horseshoe bat recordings. As part of the survey we have also recorded other bat species, providing a wealth of data to add to the Bat Conservation Trust’s National Bat Monitoring Programme, which provides vital information for effective bat conservation the UK.

Thank to everyone who took part. Your incredible efforts will help us to focus our work in key areas. It will assist both in terms of further research and targeted land management advice. Your results reports have been sent by email to you. However if you took part and haven’t received yours please email

The Survey Locations map uses tetrads to show the survey areas. Although people selected a 1km grid square to deploy their detector, the map shows a tetrad square to make it easier to view on this map. A tetrad is a 2km by 2km grid square used for biological recording.

In total the survey recorded over 1.4 million sound files. Whilst we have some great technological aids for helping us to work out which are bats and which are birds, crickets and general noise, we still need to manually check lots of the files. As you can imagine, this takes a huge amount of time!

The second map shows ‘hotspots’ or the density of greater horseshoe bats recorded. This is only based on the sites surveyed. It does not mean that if an area of the map doesn’t show any greater horseshoes that they do not occur here. The strongest colours show where there were over 25 greater horseshoe passes in one location, a great result!

As the survey progresses we hope to compile a set of cumulative maps for all years. Later this year, we hope to produce a further map showing the number of species recorded in each tetrad, so watch this space! You can view previous years results on our Devon Bat Survey menu.