Reports

The Bailiwick Bat Survey is a four year project and at the end of each year, BTO produce an annual summary report of the findings. The reports include a full species-by-species breakdown of spatial, seasonal and through-the-night patterns of activity. At the end of the four years, a final report will be produced.

Read the results of the 2021 – 2024 bailiwick Bat survey

2021 - 2024 Bailiwick Bat Survey Report

Over four survey seasons, from 2021 to 2024, 2,364 different locations across the Bailiwick of Guernsey were surveyed. Recording was undertaken on 879 different nights mainly between April and the end of October in each year, amounting to a total of 9,426 nights of recording effort across sites.

Overall, 16,192,045 five second triggered recordings were collected which, following analyses and validation, were found to include 4,019,529 bat identifications and 35,354 small terrestrial mammal identifications. There were also over 8 million identifications of bush-crickets as ‘by-catch’, for which we report species presence on a site and night basis.

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.

Read the results of the 2022 bailiwick Bat survey

2022 Bailiwick Bat Survey Report

During 2022, 622 different locations across the Bailiwick of Guernsey were surveyed. Recording was undertaken on 209 different nights mainly between April and the end of October, amounting to a total of 2,416 nights of recording effort across sites.

Overall, 3,389,138 recordings were collected which, following analyses and validation, were found to include 872,126 bat recordings, and 8,587 small terrestrial mammal recordings. Over 2 million recordings of bush-crickets and audible moth species were also recorded as ‘by-catch’, for which we report species presence on a site and night basis.

Read the results of the 2021 bailiwick Bat survey

2021 Bailiwick Bat Survey Report

During 2021, 613 different locations across the Bailiwick of Guernsey were surveyed. Recording was undertaken on 234 different nights mainly between April and the end of October, amounting to a total of 2,221 nights of recording effort across sites.

Overall, 720,011 recordings were collected which, following analyses and validation, were found to include 710,260 bat recordings, and 8,211 small terrestrial mammal recordings. Over 1.5 million recordings of bush-crickets and audible moth species were also recorded as ‘by-catch’, for which we report species presence on a site and night basis.