With temperatures now dipping below -10 C, today's been about how to keep the hummingbird feeder from not freezing (when we only have one feeder and therefore can't rotate feeders). For now, we've been replacing the half-frozen nectar every couple of hours with nectar in room temperature. As well, we take the feeder indoors for the night and hang out again at dawn. 

Happy to report that our two regulars are still accounted for.