"Different species make different noises. African, Humboldt, Magellanic and Galapagos penguins all make braying sounds (like a donkey) and each of these species has at some time been known as "Jackass" penguins as a result. Their chicks, in contrast, make a high pitched whistling noise to demand feeding. The Yellow-eyed penguin makes a trilling sound (not unlike the old "trim-phone"). The Chinstrap has a shrill, screaming voice, so loud that it is sometimes called the stone-cracker penguin. The King penguin makes a trumpeting sound. "