>> I took the hummingbird feeders down in October when the honeybees got >> too thick, put them back up when I saw more hummingbirds. Yesterday >> morning the feeder was frozen solid, I microwaved it until it thawed >> out. By 11 AM there were two hummingbirds fighting at the feeder. This >> morning there was one sitting in a shrub nearby by 8 AM. They must be >> able to hibernate overnight? Yes, they hibernate overnight. The Anna's hummingbird winters here in Arizona and breeds in January. I make sure my feeders never go dry this time of year and I don't do any winter shrub pruning to avoid disturbing nests. Leo Martin Phoenix Arizona USA