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Providing evidence to improve practice

Individual study: The effect of gates on cave entry by swarming bats

Published source details

Pugh M. & Altringham J.D. (2005) The effect of gates on cave entry by swarming bats. Acta Chiropterologica, 7, 293-299

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Install and maintain cave gates to restrict public access Bat Conservation

A randomized, controlled, before-and-after study in 2004 at a cave in a wooded limestone valley in northern England, UK (Pugh & Altringham 2005) found that cave gates with horizontal bar spacings of 130 mm and 100 mm caused significantly more bats to abort attempts to enter the cave through the gate, but gates with spacings of 150 mm had no effect on bat behaviour. The proportion of bats entering the cave decreased after gates were installed with horizontal spacings of 130 mm (without gate: 0.20–0.28 bats/30 min; with gate: 0.07 bats/30 min) and 100 mm (without gate: 0.20 bats/30 min; with gate: 0.08 bats/30 min). Gates with horizontal spacings of 150 mm had no significant effect (without gate: 0.14–0.16 bats/30 min; with gate: 0.10 bats/30 min). Bat behaviour was similar before the gates were installed and after they were removed. One cave entrance was used for the experiments (1.5 m diameter) with custom made gates (made with 15 mm diameter plastic tubing) of each of three horizontal spacings (100, 130 and 150 mm) positioned over it. Bats were recorded for 3 x 30 minute periods with the gate open (‘before’), closed, and open again (‘after’). The behaviour of swarming bats (mostly Natterer’s bats Myotis nattereri) was observed on 6–10 nights for each of three gate designs using night video recording, with gate size randomized between nights.

(Summarised by Anna Berthinussen)