Bailiwick Bat Survey

The survey was commissioned as a four-year project which began in 2021 and ran until the end of 2024.

We have completed our final surveys of the project and BTO are now analysing the data to produce the final report.

We would like to thank each and every one of our volunteers who took part in the survey – whether you joined us for just one year or all four. The survey would not have been possible without all of your hard work. Your efforts and the survey’s results have far exceeded our expectations and the findings have revolutionised our understanding of the local bat population.

You’ll be pleased to hear this isn’t the end… the survey will begin again in 2026, albeit just in a slightly different format. Watch this space!

If you have any queries, please get in touch and we’ll get back to you as soon as we can.

The survey aims to improve our understanding of the distribution and activity of the different species of bat found in Guernsey, Herm, Alderney and Sark whilst providing an opportunity for anyone across the islands to take part in this project.

Why care about Bats?

Bats are an ‘indicator species’. They can tell us a lot about the state of our environment as they are a top predator for nocturnal insects. Bats will be affected by changes in landscape, agriculture practises, development and habitat fragmentation. These changes will have an impact on many species in Guernsey but by surveying the changes in bat populations, it will indicate the wider health of our wildlife, without having to count every species.

Bats are a natural form of pest control, eating thousands of insects each night – including mosquitos! They are great for keeping bugs away from crops which provides a valuable service for agriculture and even your own vegetable patch. Bats provide this service free of charge, and without the use of pesticides.

Meet our local bats

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Nathusiass-pipistrelle-by-Daniel-Hargreaves

EA5A6963 Kulhs pip Pipistrellus kulhi Guernsey 17.08.18 - Daniel Hargreaves

Sadly, bat species around the world are vulnerable or endangered due to factors ranging from loss of habitat, diminished food supply, destruction of roosts, disease or killing of bats.

However … there are lots of things we can do to help!

To learn more, head to our ‘Bat Protection’ page.

Read the results of the 2023 bailiwick Bat survey

2023 Bailiwick Bat Survey Report

During 2023, 582 different locations across the Bailiwick of Guernsey were surveyed. Recording was undertaken on 228 different nights mainly between April and the end of October, amounting to a total of 2,260 nights of recording effort across sites.

Overall, 3,825,977 five second triggered recordings were collected which, following analyses and validation, were found to include 994,021 bat identifications, and 7,973 small terrestrial mammal identifications. There were also over 2 million identifications of bush-crickets as ‘by-catch’, for which we report species presence on a site and night basis.

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