Charles Darwin is most famous for his finches, from whose beaks he gleaned the idea that a single species might radiate into many. But he studied other attributes of birds, too—like the rhythmic ...

Birds tweet, squawk, chirp, hoot, cluck, and screech to communicate with each other. Some birds have found another way to talk, though: they make sounds by fluttering their feathers or smacking their ...

The critical threshold or frequency at which an interrupted or “fluttering” sound appears to be continuous, an aspect of human perception analogous to the visual critical fusion threshold, has not ...

When your electrical system is working normally, the two upper chambers of the heart (atria) contract and pump blood into the two lower chambers (ventricles) in a well-coordinated way. This results in ...