MA of Reader:
I was just looking at a hummingbird feeder outside my window, and I began to wonder if the sugar mixture would eventually begin to ferment. If so, how long would it take? Would it have to be really hot to help speed up the process? Would the hummingbirds get "high" off the juice?
-- LB of Poway
Even as we speak, the elves have their noses pressed against the window watching an Anna's hummingbird drinking from one of the many Alice feeders. It's Brutus, the hummer that chases all others away from his territory in screeching dive-bomb fights. One of his victims scrammed so fast that he flew into the Alice screened porch and got stuck, with his little beak jammed into the mesh. We poked his bill back out and he seemed none the worse for it. And I don't think he was FWI -- flying while intoxicated.
If you leave sugar water exposed to full sun, within a day it will start to ferment. But perhaps worse are the molds and fungus that begin to sprout. Instead of giving the hummer a nice buzz, the combination could make it sick or even kill it. They get some disease that makes their tongues swell so they can't feed at all. And the alcohol can fatally enlarge their tiny livers. All in all, you're more likely to end up with a candidate for detox than a hummer that wants to put a lampshade on its head and dance on a table.
Most experts say that two to three days in hot weather is the longest you should go without changing the water. Make that a week in cold weather. And that's assuming you boil the sugar water to kill bacteria and scrub your feeders with a bottle brush (but no soap!) every time you fill them. If you have crud inside the feeder and can't get at it with a brush, Grandma Alice says to pour in some uncooked rice with a little water and shake it around. Acts like a scouring pad.
Hummers' metabolism is so high that they're more susceptible to these things than other birds. There are many stories of reeling robins and crocked catbirds that have eaten fermented fruit from a tree or vine and end up rolling around on the lawn, giggling and telling dirty jokes.