All the time we were outside, small groups of house finches were arriving and making impatient, indignant noises, then flying off again. When we went in for lunch, more than 30 finches appeared all at once. It appears there are a lot more birds using the feeder on a regular basis than I had supposed. The house finches were eventually chased off by this flicker, who is the back yard's current alpha-bird.
Happy Snow Day, wherever you are.