This is scientific American 60 second science. I'm Christopher Intagiyata.

30 million white-tailed deer now live in North America.

That's a lot of deer.

Megan Gaul, a sensory ecologist at Vassar College in Poughkeepsie, New York.

In her Hudson Valley locale...

There is a recent estimates here that you could have somewhere between 20 and 40 deer per

square mile.

These prolific grazers have been blamed for many things,

munching on baby trees.

And that's a big problem because they are going to

prevent forest regeneration. They also change the structure of the forest understory, which is no good for birds that live there, for small rodents that live there.

And they contribute to the Lyme disease problem as tick hosts.

To all that we can now add a new accusation

that deer are altering the very acoustics of the forest

by pruning trees and changing the way sounds,

like bird calls,

travel through the trees.

Gaul and her team investigated plots of forests

where deer graze and others where they were excluded.

In each 30 by 30 foot plot,

they placed a speaker at one end playing white noise

Tones or trills and

...