Passage adapted from Christopher Intagliata, “Road Noise Takes a Toll on Migrating Birds.” ©2015 by Scientific American.
Building a road through wilderness certainly has a visible
impact on local flora and fauna—you’re physically paving over
a slice of what was once habitat. But roads have less obvious
effects, too. Like the introduction of traffic noise, which also
takes a toll. “You can see an oil spill but you can’t see a traffic
noise spill. So convincing people that it’s important is a little
more difficult,” said Heidi Ware.
Ware is an ornithologist at the Intermountain Bird
Observatory in Boise, Idaho. She and her colleagues studied
the reactions by birds to the sounds of vehicles. And they did it
without paving the great outdoors. Instead, they mounted 15
pairs of speakers on Douglas fir trees, along a ridge near Boise,
and played traffic noise. They thus created what they call a
“phantom road” through the wilderness, which boosted local
noise levels 10 decibels higher than those in the surrounding
forest.
Turns out just the sounds of traffic scared away a third of the
area’s usual avian visitors, and cut species diversity too. And
birds of multiple species were not able to pack on as much fat
to fuel their migrations when they were forced to dine to the
soundtrack of traffic.
Follow-up experiments in the lab found that, when it’s
noisy, birds spend a lot less time head down, pecking at food,
and a lot more time scanning their surroundings.
Ware says Yosemite, Glacier and Rocky Mountain National
Parks all have roads that are busy enough to produce these
effects. And, short of closing park roads to traffic, she says
things like rubberized asphalt and lower speed limits could
help cut the noise. “Glacier National Park is going to put up
signs, that instead of showing your speed and preventing
people from speeding, it’s going to show how loud their car is
on the road.” Which, hopefully, will continue to encourage
wilderness lovers to leave no trace—visible or audible.
Building a road through wilderness certainly has a visible
impact on local flora and fauna—you’re physically paving over
a slice of what was once habitat. But roads have less obvious
effects, too. Like the introduction of traffic noise, which also
takes a toll. “You can see an oil spill but you can’t see a traffic
noise spill. So convincing people that it’s important is a little
more difficult,” said Heidi Ware.
Ware is an ornithologist at the Intermountain Bird
Observatory in Boise, Idaho. She and her colleagues studied
the reactions by birds to the sounds of vehicles. And they did it
without paving the great outdoors. Instead, they mounted 15
pairs of speakers on Douglas fir trees, along a ridge near Boise,
and played traffic noise. They thus created what they call a
“phantom road” through the wilderness, which boosted local
noise levels 10 decibels higher than those in the surrounding
forest.
Turns out just the sounds of traffic scared away a third of the
area’s usual avian visitors, and cut species diversity too. And
birds of multiple species were not able to pack on as much fat
to fuel their migrations when they were forced to dine to the
soundtrack of traffic.
Follow-up experiments in the lab found that, when it’s
noisy, birds spend a lot less time head down, pecking at food,
and a lot more time scanning their surroundings.
Ware says Yosemite, Glacier and Rocky Mountain National
Parks all have roads that are busy enough to produce these
effects. And, short of closing park roads to traffic, she says
things like rubberized asphalt and lower speed limits could
help cut the noise. “Glacier National Park is going to put up
signs, that instead of showing your speed and preventing
people from speeding, it’s going to show how loud their car is
on the road.” Which, hopefully, will continue to encourage
wilderness lovers to leave no trace—visible or audible.