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Providing evidence to improve practice

Action: Create artificial hollows and cracks in trees for roosting bats Bat Conservation

Key messages

Read our guidance on Key messages before continuing

  • One study evaluated the effects of creating artificial hollows and cracks in trees for roosting bats. The study was in Australia.




  • Use (1 study): One replicated study in Australia found that eight of 16 artificial hollows cut into trees for bats, birds and marsupials with two different entrance designs were used by roosting long-eared bats.

Supporting evidence from individual studies


A replicated study in 2015–2016 of 16 trees within a timber production forest in New South Wales, Australia (Rueegger et al. 2017) found that half of the artificial hollows created in trees were used by long-eared bats Nyctophilus spp., and the design of the entrance did not have a significant effect on use. Eight of 16 artificial hollows were used by long-eared bats, including one of six hollows designed for bats and seven of 10 hollows designed for marsupials and birds, although use of the two designs did not differ significantly. Artificial hollows were created in 16 trees (33–54 mm diameter at breast height) within a forested area of 4 ha. In September 2015, one hollow (35 cm high x 9–20 cm wide and 4 m above the ground) was created in each of 16 trees using a chainsaw. A section of tree (4 cm deep) was reattached to the front of each hollow with an entrance hole either at the base (designed for bats, 38 mm diameter) or the top (designed for marsupials and birds, 38 or 76 mm diameter). Each of 16 hollows was monitored over 12–15 months in 2015–2016 with heat/motion activated cameras.

Referenced papers

Please cite as:

Berthinussen, A., Richardson O.C. and Altringham J.D. (2019) Bat Conservation. Pages 67-140 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.