In the previous post, Drinking Birds, I promised to test whether radiant energy from the sun or a light bulb would power the 'drinking' bird. I soaked the head of my extra bird overnight in a glass of water. This loosened the glue holding its hat, tail feathers, and plastic beak so that they could be easily removed. I used a small razor knife to shave the red fuzz off the bird's head. I spray painted the bottom black and the top white because black is a better absorber of radiant energy than white. As you can see in the following video, sunlight will power the bird.
Let's just say the bird is 'drinking sunlight'.
Note that in the video, the bird is in a relatively shaded spot. Placing the bird in direct sunlight causes it to go through its 'drinking' cycle at a faster rate. Within an hour, the sun had moved placing the bird in shade and it stopped bobbing. Also, the inverted cup keeps the bird from tipping upside down just as the rim of the glass does in its water-drinking cousin.