Response of bats to light with different spectra: light-shy and agile bat presence is affected by white and green, but not red light

Published source details Spoelstra K., van Grunsven R.H.A., Ramakers J.J.C., Ferguson K.B., Raap T., Donners M. & Veenendaal E.M. (2017) Response of bats to light with different spectra: light-shy and agile bat presence is affected by white and green, but not red light. Proceedings of the Royal Society B: Biological Sciences, 284.
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This study is summarised as evidence for the following.

	Action	Category
	Use red lighting rather than other lighting colours Action Link

Use red lighting rather than other lighting colours

A replicated, controlled, site comparison study in 2012–2016 at eight forest sites in the Netherlands (Spoelstra et al 2017) found that red lighting had higher activity for one of three bat species groups than white or green lighting, and similar activity was recorded for all three species groups in red lighting and darkness. For Myotis and Plecotus spp. more bat passes were recorded in red light (66) and darkness (67) than in white (31) and green light (22). For Pipistrellus spp. fewer bat passes were recorded in red light (5,940) and darkness (3,655) than in white (17,157) and green light (9,695). None of the light treatments had a significant effect on the number of bat passes recorded for Nyctalus or Eptesicus spp. (red light: 495; white light: 719; green light: 950; dark: 521). At each of eight sites, one 100 m transect was set up for each of four treatments (red light, white light, green light or left dark). Five 4 m high light posts were installed along each transect. Lights (8 lux) were turned on from sunset to sunrise. Bat detectors recorded bat activity for 5–15 nights/transect in June–July and August–September in each year between 2012 and 2016.

(Summarised by: Anna Berthinussen)