Why do birds sing?

Birds sing to advertise their fitness for the benefit of both potential mates and potential rivals. Their songs also announce that they have secured a territory. Most birds who sing are male, and birds like nightingales have been known to sing all night long to demonstrate their prowess.

The song of a bird tells a great deal about it. The song can let other birds know how old the bird is. A complex song needs to be learned over time. Songs may let listeners know that the bird has survived the dangers that come with being a bird and that he most likely has some experience with raising chicks.

In some species, when a pair of birds get together, they sing a duet to strengthen their bond and let other birds know they're already paired up. Some songs are simply to let a mate know that there's a food source nearby or to let one partner know where the other one is. There's even some speculation that birds sing for the joy of it, even though singing requires a great deal of energy.

Most birds sing around breeding time, which would be early spring to summer, though other birds sing all year long.