53K views · 524 reactions | The ruffed grouse is hard to see, but its drumming is a fixture of many spring forests. If you look closely, however, you'll see the male’s signature display doesn’t involve "drumming" on anything but air! © David & Laura Hughes | West Virginia Nature Conservancy | Facebook

Male ruffed grouse “drum” in springtime as a way to establish territory and to attract females. Although it looks as if the sound is caused by the bird’s wings hitting its chest, the sound actually comes from small sonic booms. The wings beat up to 5 times per second, causing the sound waves to stack up until they create a penetrating shock wave that creates the boom. Male grouse usually perform on a “drumming log,” which might help project the low-frequency sound. Drumming exerts a remarkable a