This is Scientific Americans 60 Second Science.

I'm Karen Hopkins.

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It may not be the most melodious bit of bird song you'll ever encounter.

But this particular call, issued by a Tufted Tit Mouse,

conveys important information about the presence of potential predators. But only if other birds can hear it. Unfortunately, near a highway, traffic sounds can drown out such alarm calls.

Scientists have long observed a decrease in wildlife population in habitats adjacent to major roadways, and many figured it was the noise that drives creatures to high tail at some place more remote.

But it could be more than mere annoyance that keeps animals away. The inability to hear

potentially life-saving calls could also be a factor. That's according to a study in

the journal biology letters. To test that theory, Aaron Grade and Catherine Seaving at the University of Florida got hold of a

Tit Mouse alarm call, produced by a captive individual that had spotted an owl.

They then played this alarm call from speakers mounted in different locations in Florida State Parks.

Some of the spots were noisy, along Interstate 75 or U.S. Route 441.

Others were more secluded and relatively quiet.

The scientists then observed the reactions of Cardinals to these broadcasted declarations of danger.

Because Cardinals and other birds often eavesdrop on the talk of Tit mice for news of impending peril.

In the quiet areas, Cardinals clearly responded to the Tit Mouse alarms.

They froze in place, stopped singing, and scanned the area for predators.

But in the noisy places, Cardinals paid the warnings no heed and continued their regular activities.

It's not completely clear whether the Cardinals could not hear the calls

or if they were simply too distracted by the traffic to respond. Either way, looks like some

birds should seek the road less traveled, or travel the region's less

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