I agree with mblan13--7-10 days is too long between cleanings to be safe for the birds. If it takes that long to empty the feeders, fill the feeders only a third of the way, and store the extra nectar in the refrigerator. I have ten feeders. Four of them get depleted and need to be cleaned and refilled every day; the rest are refilled every other day. Our customers include a gang of the gigantic "hummers" (hooded orioles) part of the year, so they help. But even when it is just the hummers, 2-3 days is the longest the feeders last before refills are needed. Which is fine, because they would need to be cleaned anyway. It helps to choose an easy to clean feeder; it takes about one minute to clean and refill one of mine.

Marilyn, a bear knocking out my kitchen window would make me crazy! Not in the daytime, but won't they get bolder? Deer do. About feeders, my ones on shepherd's hooks in the front yard have been okay at night. However, we have had to bring the deck feeders in at night for about a month because they were raided several times, each time rougher and more aggressively.. The first few times, they were just dry in the morning, and a suet feeder was not touched. Then the;y were dry and one knocked down, suet still left alone. Finally, .they were knocked down and the suet feeder completely eaten out, mud in the birdbath underneath. We thought maybe raccoons. If I thought it was a bear, I would want to buy an elephant gun. I certainly would have to bring them in at dusk because I'd be too afraid to venture out there at night.

He'll join the fight at another nearby food source. I would consider planting some flowers they like, like Salvia. They are real cheap at the nurseries this time of year. And this time of year there is usually enough rain to sustain them without you there to water them. Donna, VA

This is a very old thread, but I'll comment because I'm trying to figure out why hummingbirds prefer old nectar over new. I suspect the OP's fresh good was competing with someone else's older food nearby, and the hummers prefered the older food. I have identical feeders, and my Anna's will ignore the freshly filled one in favor of the older one until the old one is empty, then they'll do the same when I refill it- ignoring it until the older one is dry. The behavior is clear and obvious, and seems to be something they can smell. I suspect they are attracted to the odor of a tiny bit of alcohol in the older food, but maybe something else. They fly up, hover a second, and go to the oldest one. I switch the feeders around and try all sorts of tricks, but they know which has older food, and that is definitely their preference.  I'm in the cool PNW, and my feeders are used up in a week, so it won't be much alcohol. Behavior might be reversed if the nectar ever got very old. I might test that this summer.