On a recent hike in Virginia, a song burst out of a bush beside us. The white-throated sparrow riffed on their usual song, experimenting with a gravely "sweet can-a-NA-da can-a!" "Jazzy!" We laughed to each other. I don't usually expect birds to sing in their winter habitat. Birds' songs are typically used to attract mates and defend territories, and therefore are most useful in spring and summer. So, we figured we were hearing a young male practicing for the coming year. As it turns out, that was only part of the story.