Calliopes are the smallest hummingbirds in the U.S. and the smallest birds in North America. In the picture below are two rufous hummers, some female hummingbirds, and, see the one with the spot of color on its throat? I think that’s an immature male black-chinned hummingbird.In the picture below, next to the rufous, is a male black-chinned hummingbird.This last picture looks like I photoshopped the rufous to make it look even more orange than usual, but I didn’t. I don’t have Photoshop, darn it. It was just the light, hitting at a strange angle. Rufous hummingbirds are bright, but this one looks electrified.