World’s first hummingbird-like unmanned aircraft system takes flight
gizmag.com
gizmag.com
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.