We had a particularly brutal cold spell in Maine from February 3-6, with temperatures falling below -20 °F and winds exceeding 60 mph. The wind chill values approached -50 °F here in central Maine. As we struggle to tolerate intense cold and biting wind chill, we have to marvel at the ability of our wintering birds to deal with such intense weather. Here is a link to a short talk (in Pecha Kucha style) that I gave as an overview of the remarkable adaptations birds have to winter temperature stress: https://www.youtube.com/watch?v=CaYZkGA0Et8