How does an owl find mice in the dark?

At night, the field is dark and still. A little mouse scurries through the long grass. High on a fence post, a barn owl sits and waits.

Close your eyes for a moment and listen. Can you hear sounds around you, even in the dark? So how does the owl find that mouse when it can hardly see it?

Every step the mouse takes makes a rustle, which means a soft, crackly whisper of sound. Its paws brush the dry grass and leaves. The owl listens hard for that rustle.

The owl's face is round and flat, like a little dish. The feathers on it catch the rustle. They send the sound toward the owl's ears, the way a cupped hand catches sound.

The owl's ears hide under the feathers on each side of its face. You cannot see them, but they are there. Its ears are lopsided, which means one is higher than the other.

Because the ears are lopsided, the rustle reaches them a tiny bit differently. One ear hears it a little louder than the other. That helps the owl tell where the sound comes from. What do you think the owl does with its head now?

The owl turns its head, slowly, bit by bit. It stops when the rustle sounds the same in both lopsided ears. Now its face points right at the mouse.

The owl spreads its wings and flies down to that exact spot. The mouse is hidden under the grass, but the owl knows where it is. Its ears found the mouse, not its eyes.

The mouse makes a rustle, and the owl's lopsided ears show it where to fly. So the owl finds the mouse with its ears, even in the dark.

The dark field is quiet again. Back on its fence post, the barn owl sits still, its round face turned to the long grass.