Light Pollution May Actually Help Some Migratory Birds
There is something unavoidably sad about the realization that, for some people, the stars are no longer visible due to "light pollution." And it's not just sentiment: Research has shown light pollution can intensify air pollution and has correlated brighter neighborhoods with higher breast cancer rates. For at least one species, however, increasing light pollution has been helpful.
According to a recent survey of the common redshank, a migratory bird, in the Forth estuary of Scotland, brighter nights have increased the bird's nighttime foraging success. The estuary, which is home to thousands of migratory birds each winter, is protected and pristine. The area, however, is surrounded by the structures of one of Scotland's most industrialized coasts. A nearby power generation plant and oil refinery contribute significant amounts of light pollution to the area.
Using radio transceivers and posture sensors Dr. Ross Dwyer, of the University of Exeter, recorded the location of 20 tagged redshanks. The posture sensors recorded the number of times the birds bent down with their heads, indicating a feeding motion. "Artificial light from industrial areas strongly influenced the foraging strategy of our tagged birds," Dwyer explained. "It was as if the 24-hour light emitted from lamps and flares on the Grangemouth oil refinery site created, in effect, a perpetual full moon across the local inter-tidal area which the birds seemed to capitalise on by foraging for longer periods at night and switching to a potentially more effective foraging behaviour to locate prey."
Of course, this finding only represents part of the story. Light pollution has been shown to have a negative impact on some animal species, including turtles—hatched turtles have wandered towards lights, away from the sea—and other migratory birds to collide with buildings and other structures. Perhaps more important for the redshanks is that even as their foraging becomes easier, their primary prey source, insects, may be suffering from increases in ambient light.