Page 62 - BBC Wildlife Volume 36 #11
P. 62
NEWS FEATURE
How does artiicial light afect other wildlife?
INVERTEBRATES BIRDS
Light pollution disturbs Several species such as
feeding, breeding, robins and blackbirds sing
predation and movement. under streetlights without
Up to one-third of moths clear harm, but others – such
lured to night lights are as long-eared owls and black-
estimated to die as a tailed godwits – are sensitive
result. Egg-laying female to artificial lighting. Bird
insects may be attracted strikes on tall, lit buildings are
away from water. a major cause of mortality.
Sky glow: around
80 per cent of the
world’s people live
under light-
polluted skies.
Globally, light Lightbulb: Mitsuhiko Imamori/Minden/FLPA; blackbird: Philippe Clement/naturepl.com; satellite image: Getty
pollution is growing
on average by six
per cent each year.
consequences, too. Red safety lighting is The light did not prompt increased hunting birds. We lack comprehensive studies.
used on aircraft, ships, tall buildings and by bats, suggesting the attraction was not It is dangerous to say any lighting is bat-
shorelines, and also on wind turbines, down to opportunistic feeding on insects friendly. Bats are not neutral to it.”
where it may worsen the problem of drawn to the light, but something else, This news will trouble conservationists
thousands of bats and birds dying each perhaps navigational. who are already worried about the
year due to collisions. A study published “Migratory bats may be more susceptible lethal attraction of wind turbines to
by The Mammal Society in 2016 to light sources of specific wavelength bats and birds. They die after becoming
suggested that wind turbines are among spectra, because vision may play a more confused into colliding with the
the largest causes of mass bat deaths dominant role than echolocation during blades, or following barotrauma – lung
around the world. migration,” Voigt suggests. “Our findings damage caused by sudden air-pressure
The drive to switch to ‘green’ and call for caution in the application of red changes near turbines. The animals’
‘eco-friendly’ forms of renewable energy aviation-safety lighting, particularly on wind natural migration routes often involve
is of course hugely important, but turbines, as this light colour might attract navigating across large offshore wind
not necessarily ‘bat-friendly’ in itself. bats, leading to an increased collision risk.” farms which have been lit up by red
As Dr Voigt, lead author of the new light to alert aircraft and shipping pilots.
research, points out: “The replacement Exploring alternatives It has been difficult to determine
of conventional lighting with energy- Finding a better solution is complex. precisely how many bats are affected,
saving LEDs is a worldwide trend, Dr Voigt’s team has proposed exploring with many dead animals thought to fall
yet consequences for animals and alternative lighting such as infrared, as is at sea, while bodies are also hard to find
ecosystems are poorly understood.” used by pilots. “Birds are also attracted to on land. One innovative study led by
Voigt’s team tested the responses of red light, and less so to green light,” he says, Fiona Mathews, Chair of The Mammal
migrating bats to red, white and green “therefore green lighting has been used as Society, used sniffer dogs in a bid to
light wavelengths. They found different a measure to avoid bird collisions on and calculate how many bats were killed by
light colours triggered changes in offshore, such as on oil-drilling platforms. It wind turbines. Previously, the BCT had
behaviour, especially with the soprano looks like the effect of green light, however, reported that at some sites in Europe
pipistrelle and Nathusius’ pipistrelle. is also quite strong on bats compared to and the USA fatalities are already high
62 BBC Wildlife November 2018
