Hi, Dotty. I got my first over-wintering Anna's hummingbird visitor last year, right about this time. This year, my winter visitor showed up in late September, right where I had my window feeder last winter. Good memory.

There is a fascinating research paper that discusses your questions and many more about feeding hummingbirds. If I can find it (not so good memory), I'll post a link. The researchers found that the sugar concentrations of North American flower nectar range from about 50 percent sugar, or about 2 (water) to 1 (sugar), to 5 (water):1 (sugar). Most summer flowers were 3:1 or 4:1. Apparently, hummers drink only when they're hungry and stop when they're full, on a calorie (not volume) basis, so the higher the sugar concentration, the more attractive the nectar--and the less time a hummer will spend feeding at that high-energy source. In winter, I use a 3:1 solution until temperatures drop into the low-20s, when I shift the solution to 2:1. Increasing the sugar lowers the freezing point and gives the birds more calories with less effort. The downside is that you won't see them as long at your feeder. But even that works out well, because more hummers get access to the feeder, instead of just one bird guarding the area for half the day.

On a separate note, I have found that the traditional hanging tube feeder drains quickly in the rain. Rain runs down the outside of the feeder, down the tube, and pulls the nectar out with it. I switched to a small window-mounted bowl-type feeder, which has a cover and a little overhanging rain shield, but rain that blows onto the bowl cover drains into the holes and dilutes the nectar after a day or two. I think feeders with little plastic flowers might not allow as much water to run into the bowl. In any case, enjoy your Anna's!

Today I noticed one really going for a flowering loquat tree.

Thanks so much weed tree. I made my nectar weaker than that, so I'll mix up another batch tomorrow. Thanks for confirming that the sugar lowers the freezing point. I have it in a protected place so it should freeze too easily. I've resisted putting up a feeder before, even though I have seen Annas in November before, but this year, I succumbed....they are such neat birds. bboy, until yesterday they were feeding on flowers but they sure found the feeder in a hurry! They have only overwintered in this area for the past 3 - 5 years.

Oops--my report of maximum nectar sugar concentration in garden flowers was too high. Most flower nectars top out at about 30 percent sugar, which is equivalent to about 2 parts water to one part sugar. After reading "Can u give a Hummer too much sugar??" on the Hummingbird Garden Forum, I now think it's better to feed hummers at a 2:1 all winter. Anything less is really a drain on their energy. And the best thing you can do in winter is to warm their nectar. They expend a huge amount of energy maintaining body heat when drinking cold nectar--to the extent that a very cold 4:1 solution could be a net loss of calories and result in hypothermia.

An understandable research paper on sugar/water concentrations is linked below.

Here is a link that might be useful: Hummingbird nectar research summary

That's an interesting research, but it addresses more "attracting hummers to your feeder", rather than giving them the best mix to survive in wintertime. I also checked the g/w forum (thanks, I didn't realize there was one). It's quite cold here, so I'll mix up a new batch at 2:1 for Anna this morning.

I'm not sure I'd worry too much about hypothermia. When the weather is very cold or food in very short supply, over wintering hummers like the Anna's enter a sort of stasis or suspended animation called torpor that significantly slows down their metabolism. They are able to survive extended periods of time under these conditions. And one of the reasons the over wintering range of Anna's has extended as far as it has is the amount of winter forage the birds are able to find in this area. Nectar is only a small portion of their diet - they need the protein from insects that they find in midair, on trees and branches and under the bark.

The short side of the story is they'll survive winter with or without our help :-) But it is so much more entertaining to entice them close with feeders and enjoy their activity and antics all winter long.

I haven't put up my feeder yet - it's on my list of things to do today once I finally dispose of the pitiful basket of ivy geraniums hanging in its place - but the Anna's are still active at my hardy fuchsias and remarkably, a still blooming (and budded) 'Golden Delicious' salvia that I plan to move into my sunroom for winter.

I use a 3:1 sugar ratio in winter and a 4 or 5:1 ratio in summer (if the feeder is out at all during that period). I have only had the feeder freeze solid once during winter but it was in a very well protcted location. I just brought it inside and nuked it for a few seconds :-)

Last year with the extended cold, I had two feeders; one outside and one inside. When the outside one froze, I brought it in to thaw, and put out the inside one.

Weedtree,
I use only the flat tray type hummingbird feeder and there is no dripping or diluting, but it is under an eave right outside my door.
The perch give them a place to sit and rest and we get to see them for long periods. And this feeder comes apart easily for thorough cleaning.

Also the Seattle Audubon does NOT recommend adjusting the sugar mixture. It should be 4 to 1 YEAR ROUND. I use 1/4 cup sugar to 1 cup boiling water.

During really cold temps, I use one of the 8 hour handwarmers and place it under the feeder into a bubble wrap pocket I've taped on.
If I'm home I try to put indoor warm food out first thing in the morning and alternate two feeders.

Here is a link that might be useful: seattle audubon

Don't forget to have water available somewhere for the birds.

During the cold spell all the small ponds are frozen over, so putting out a bird bath/ water station is very important. Or using some christmas lights or birdbath heater to keep it thawed is very important.