Real hummingbirds are the most energy intensive birds. They have a very low margin for error, a few hours without feeding at best. http://www.blurtit.com/q8900

Real hummingbirds are the most energy intensive birds. They have a very low margin for error, a few hours without feeding at best. http://www.blurtit.com/q890088.html http://www.blurtit.com/q890088.html "A 4-gram hummingbird has a basic metabolic rate of 1,400 calories per gram. In repose, a hummingbird's metabolism rate is 25 times that of a domestic fowl. If a person had such a high metabolic rate, he would have to eat twice his body weight daily, his temperature would be 750 degrees F, and he would consume 155,000 calories per day." It's probably marginally better than helicopters.