The male peafowl, the peacock, is best known for his head crest and amazing tail called a train. The train with its ocelli, or eyes, comes into its full splendor when the peacock is about 2 years old. With a wingspan of nearly 5 feet and a train just as long, the male peafowl is "one of the largest flying birds in the world," according to the Smithsonian's National Zoological Park.