Scientists call this theory the auditory template hypothesis. In this theory, song learning begins at about ten days after hatching and continues for about 40 days. Baby birds then practice their songs through the fall and winter. To communicate, birds combine songs and other vocalizations with certain behaviors and outward appearances. Males tend to sing more than females, and they sing more in the spring.
Songs help proclaim territory, attract mates, and maintain a pair bond.
Some birds like gulls and parrots have no songs. Instead they use complex calls to defend territory and attract mates. Oilbirds and cave swiflets use vocalizations to maneuver in the dark, a process called echolocation. The ruffed grouse and mourning dove make sounds with their wings and woodpeckers with their beaks. Most songbirds have several songs and calls.