Do Hummingbirds Sleep?

http://www.cvco.org/science/audubon/Nov2002article.htm

We think of hummingbirds as being migratory, and most of them are. That does not mean, however, that they cannot survive cold weather, as hummingbirds don't sleep the way other birds or animals do. They practically go into hibernation every night. Their body temperature, heart rate, and breath rate drop significantly. This is called torpor (TOR-per). These go up in the morning, and the hummer wakes up and goes about its business. In this country, there is a western species called the Rufous Hummingbird that has been seen many times on the east coast in the middle of winter and has survived just fine. Many Rufous Hummingbirds nest in Alaska and arrive there when it is still quite cold. There are also hummingbirds in the rainforests in South America that live high in the mountains, where it can be quite cold. When they go to sleep at night the temperature  drops to near freezing, yet the hummingbirds survive there just fine.