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Thursday, 16 November 2017 10:59

Think of bats when searching for the light

When thinking about the need to replace our outside back light I wouldn't have given the needs of bats a fraction of thought, that was until a press release arrived from Philips Lighting hailing the benefits of their new bat friendly lighting, the one pictured below showing an atmospheric red mist of light falling on prime bat hunting grounds.

bats2 Philips-LightingLooking into this whole issue of lighting and bats, I found out that most species of bat are very sensitive to different types of lighting, and lighting with high ultraviolet rays is a huge barrier for them. So in the case of my outside back door light, if it's placed to shine near the exit hole of a roost, the bats will be fooled into staying in bed longer and miss out on feasting on insects in the critical twilight period when many insects are most abundantly on the wing. Bearing in mind the tiny cute pipistrelle bat, the one we're most likely to see in this country, can polish off 3,000 blood sucking, itch-inducing midges and mosquitoes a night, then I wouldn't want the poor creatures to go starving at all!

Nevertheless, the thought of an extra complication in choosing a light fills me with dread. I'd mentally pledged never to repeat that mind-boggling shopping trip choosing some kitchen light fitting where I lost three hours of my life. I'm thus going to take guidance from the brilliant work of Emma Stone from the Bats and Lighting Research Project, at the University of Bristol. She's written the authoritative 'Bats and Lighting - Overview of current evidence and mitigation' for the Bat Conservation Trust. A quick internet search of this and you can download the 78 page PDF document which makes surprisingly interesting reading.

No artificial light at all is actually the best option for most bat species, but in the real world where light is used - and it's increasing globally at a massive rate - then in my immediate case, an outside light that only comes on via a sensor for a short period when you've gone towards the back door is the best option, as well as avoiding lighting with high levels of bat-harmful UV rays.

bats Philips1The other aspect of lighting that really messes up with bats, and this is where the Philips Lighting comes in, is the use of street lighting that's on throughout the night in areas that they previously hunted and foraged. They love to go along trees and hedges as regular happy hunting grounds, but if the wrong lighting is used it becomes a barrier that shuns them away. Some species have been found not to cross an area of such lighting so hard-wired are they, that it is actually becomes to them a piece of daylight full of dangers from the likes of sparrowhawks and cats.

This might seem a bit stupid, but all species, including ourselves, are hard-wired for different situations - who amongst us would like to go on a foraging trip down your average Market Street or supermarket aisle if it smelt of offal (awful) putrefying flesh? That would be a hard-wired DNA barrier surely. And maybe bats aren't hard-wired like us into being tribalistic/nationalistic/proud however intellectual we think we are. I think of our species though full of genius invention and compassion, as sadly being attached to ideas that lead us to murder and industrialised mass slaughter. Even the looking down on people with different accents or which end of a town you come from shows the extent of our hard-wired DNA problem - and it's so difficult to erase. Go on, just try it. God probably looks down more fondly on the bat.