Drinking Bird

PIRA: 4C31.30

The bird's head is made wet and then allowed to dry.  As the water evaporates from his head, it takes some thermal energy with it.  Since the volume remains the same, and the temperature decreases, the pressure inside the head decreases as well, drawing the red liquid up the neck.  When the bird's center of mass is raised above the hinges at the legs, he tips over.  A glass or beaker of water placed in front of him will keep the beak and head moistened, allowing him to drink for days.