A male rufous hummingbird checks out a flower before moving on to a man-made hummingbird feeder. According to the Cornell Lab of Ornithology, the rufous hummingbird is one the more feisty of hummingbird species in North America and is one of the more aggressive hummingbirds. It notes that the males are more territorial than the females, which are green and orange. Hummingbirds feed mostly on nectar from flowers, but also eat insects. Like other hummingbirds, the rufous travels to Mexico for the winter.