On July 3, 2006, this Anna's Hummingbird was taking a bath in one of our bird bath plates. When watching this video in slow-motion, you can see that the head is totally under the water.
Hummingbirds are especially fond of water features. They don't like deep water or fast moving water for bathing. They prefer an area where water runs over the edges of plates or in a plate where the depth of water is less than an inch.
You can read more about the Anna's Hummingbird in the Backyard Birds section.
Check out the links to the Broad-tailed Hummingbird and the Rufous Hummingbird where you can read about them and watch videos of them.