Unlike most birds, hummingbirds have iridescent feathers. Iridescent feathers glitter and shine in the sun. Hummingbirds are often dazzling combinations of greens and reds or greens and blues. Others are violet, orange, golden, silver or other combinations only Mother Nature could dream up. All hummingbirds have long bills to insert into flowers. Some hummingbirds have special bills to fit in specific flowers. Hummingbirds are the only birds that can fly backwards.