Action Synopsis: Bat Conservation About Actions

Minimize noise levels within caves

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • One study evaluated the effects of minimizing noise levels within caves on bat populations. The study was in the USA.




  • Behaviour change (1 study): One controlled study in the USA found that experimental cave tours with groups that did not talk resulted in fewer bat flights than when groups did talk, but talking did not have an effect on the number of bat movements.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A controlled study in 1997–1998 in one cave in Arizona, USA (Mann et al 2002) found that experimental cave tours with groups that did not talk resulted in fewer take-offs and landings by a roosting cave myotis Myotis velifer colony than when groups did talk, but talking did not have a significant effect on overall colony activity. Bats had fewer take-offs and landings when groups did not talk (take-offs: average 13; landings: average 12) than when all members of the group talked (take-offs: average 16; landings: average 14). Overall activity of the colony (all bat movements) was similar when groups did not talk (average 59% of colony active) or when all members of the group talked (62%). A colony of 1,000 cave myotis bats roosted in a large cluster within one room of the cave. Experimental tours were carried out through the room with five replicates of each of 24 treatment combinations. Treatments included voice intensity (no people talking, all members of group talking), light intensity and colour (no light, low intensity white light, full red light, full white light), and size of tour group (0, 1–3 or 6–8 people). A total of 120 experimental cave tours were carried out between April and September in 1997 and 1998. Bat behaviour was observed with a night-vision video camera and infrared lights.

    Study and other actions tested
Please cite as:

Berthinussen, A., Richardson O.C. and Altringham J.D. (2021) Bat Conservation: Global Evidence for the Effects of Interventions. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.


Where has this evidence come from?

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Bat Conservation

This Action forms part of the Action Synopsis:

Bat Conservation
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