This is Scientific Americans 60 Second Science.

I'm Jason Goldman.

It's hard to be a bird in our human-dominated world.

You can barely hear yourself sing, let alone hear the songs of your friends,

and you can forget about hearing a predator.

Noise is almost everywhere, especially... and you can forget about hearing a predator.

Noise is almost everywhere, especially noise from traffic.

A whopping 83% of the surface of the continental US

is within just one kilometer of a road.

Researchers have tried to assess the impacts of road noise on animals

by understandably looking at animals living near noisy roads.

The problem is that noisy roads are both noisy and well their roads. It's hard to separate the two.

And so we figured out a way to have just the noise without any of the other effects of a road and to do that we ran speakers through a forest.

Where there was no road.

Chris McClure, a biologist at Boise State. where there was no road.

Chris McClure, a biologist at Boise State University and the Paragrin Fund.

He and his team built their Audio Phantom Road at a popular stopover site for birds in Idaho

as they fly south for the winter.

While the noise kept lots of birds away,

some stuck around, but they had trouble putting on enough weight

to fuel the next leg of their migratory journey.

They have to fatten up, but they also have to not get eaten by a predator.

...