Unhappy Hummies

I think this is a clue as to what kind of a winter we're going to have.  

It's suddenly turned very, very cold.  I believe the temperature was somewhere around 23 degrees this morning.   A couple of bewildered hummies attended the feeder and then left but came back as soon as I cleaned, unfroze and refilled the feeder.  I hope they stay around this winter although I can't understand how they survive the cold.  Bless their little hummie hearts.