Weeping Willows?

What do trees do when they’re dying of thirst? They cry out loud!

Scientists have recently learned that some trees give off ultrasonic chirps--sounds that are too high for humans to hear--during a drought. And the thirstier the trees get, the more they chirp.

Sound weird? Not to bark beetles, says one scientist who has been studying the sounds. The insects, which attack sick trees, may listen for the chirps.

The trees’ chirps are being recorded to see if they help the insects tell an unhealthy tree from a healthy one. “When I slowed down the tape to hear the chirps,” the researcher said, “they sounded like bongo drums or popcorn popping!”