Create artificial hollows and cracks in trees for roosting bats
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Some bat species roost within naturally forming crevices and cavities within trees. Similar features could be created artificially in existing trees to provide roosting opportunities for bats.
A study that uses snag recruitment alongside other practices for forest restoration is described in ‘Threat: Residential and commercial development – Create or restore bat foraging habitat in urban areas’.
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.Study and other actions tested