Drinking Bird
Simply moisten the bird's head with water, place it next to a full glass of water and watch as the bird periodically dunks its head into the glass for a "drink." The bird's head is covered with a material that absorbs water, ensuring that its head remains cooler than its body. The difference in temperature between the head and body creates a vapor pressure differential within the bird which causes the liquid to rise in the neck. When the liquid enters the head, it causes the bird to tip over into the water for another drink.