Join sound recordist Greg Budney in our Video of the Week and learn about one of the first sounds of spring: the wonderful whistled song of the Northern Cardinal. Both male and female cardinals sing, and their songs bringing a cheerful sound to the gray days of late winter and early spring. | Cornell Lab of Ornithology

A bird's body heat will warm the air between its feathers. On cold days, birds like this Northern Cardinal fluff up to trap as much air in their feathers as possible. Learn about other strategies birds use to get through snow storms: http://ow.ly/NIWR30iOnU7 | National Audubon Society