A Black-capped Chickadee, a year-round bird in Milwaukee, perches on a branch at the Schlitz Audubon Nature Center. With the sun shining a little more lately, you may have noticed more birds chirping ...

I was recently creeping through a clearing of downed trees in a wooded Brooklyn park with my iPhone in hand. Birds were singing everywhere, but through the din, I was recording a peculiar song: It was ...