During winter there are several species of little gray birds that frequent the buffet at our feeders.
Chickadees live in my neighborhood all year long. Philadelphia is one of those places where the Carolina Chickadee and the Black-capped Chickadee mix. I can never tell the species apart and have stopped trying. When birders around here say they can tell the two species apart, I am skeptical.
Here is a photo gallery of several little gray birds to help you identify them. Thanks to the photographers who shared their photographs through Flickr and Creative Commons.