Table 2. Results of B. barbastellus radio-tracking surveys carried out in summer 2022.

‘Max passes’ represents the maximum number of passes recorded (within an hour of sunset) across all detectors during the acoustic surveys conducted in 2021. ‘Colony prediction’ represents predictions based on the ROC analysis cut-off threshold. For all sites where barbastelles were caught but not tagged, the individuals were adult males and were considered unlikely to yield identification of a maternity colony and so were not radio-tracked. Adult females were prioritised for radio-tracking over juvenile bats.

							Radio-tracking
Site identity	Max passes	Colony prediction	Adult females	Adult males	Juvenile females	Juvenile males	Tagged bats	Colony located	Emergence count
Wiltshire
1	14	Present	1	0	0	0	1	Yes	21
2	6	Present	2	2	0	0	2	No	–
3	0	Absent	0	1	0	0	0	No	–
South Midlands
4	57	Present	2	2	3	3	2	Yes	52
5	44	Present	4	2	0	0	2	Yes	42
6	0	Absent	0	0	0	0	0	No	–
West Sussex
7	10	Present	0	0	1	0	1	Yes	22
8	19	Present	0	2	0	0	0	No	–
9	6	Present	0	1	0	0	0	No	–
10	10	Present	0	0	0	0	0	No	–
11	0	Absent	0	0	0	0	0	No	–
Herefordshire
12	32	Present	4	0	0	0	3	Yes	14
13	16	Present	1	1	0	0	1	No	–
14	4	Present	0	0	0	1	1	No	–
15	14	Present	0	0	0	0	0	No	–
16	4	Present	0	0	0	0	0	No	–
17	0	Absent	0	0	0	0	0	No	–