We have what I believe to be Annas here in Portland Oregon this winter. They are at our feeder pretty much all day. It seems like there are maybe 2 pairs or so. They made it through a week of sub-freezing temps in November but the rest of the winter has been on the milder side. When the feeder does freeze I bring it in to thaw in the morning. If it needs to be changed or refilled, boy, they let us know!! Love their little voices. One practically landed on my arm when I was hanging it after a refill! I know they rely on it so we're sure to keep them fed.