This species, like other dippers, is equipped with an extra eyelid called a "nictitating membrane" that allows it to see underwater, and scales that close its nostrils when submerged. Dippers also produce more oil than most birds, which may help keep them warmer when seeking food underwater. The song consists of high whistles or trills peee peee pijur pijur repeated a few times. Both sexes of this bird sing year round. Learn more about American Dipper