Perched on a flowering shrub on a windy Andean mountainside, the tiny Ecuadorian Hillstar hummingbird chirps songs of seduction that only another bird of its kind can hear. As the male sings, he ...

Berkeley -- The beeps, chirps and whistles made by some hummingbirds and thought to be vocal are actually created by the birds' tail feathers, according to a study by two students at the University of ...