I have always wondered why birds sing. At first, I thought they sing because they just enjoy it but I was recently introduced to a text that said birds sing for several reasons.
In the first place, birds sing in order to communicate with other birds, to warn other birds of danger, and to locate one another.
In the second place, for a bird, it’s not enough just to ‘sing’, they need to be pretty good at it, because a good singer means a healthy bird and that’s important for finding a mate. A healthy bird can sing longer and more complicated songs, while a less healthy bird can not.
In the third place, birds sing to stake a property. They sing to warn other birds to stay away from their property. For example, the author of the text says that a robin might stake a claim on a piece of land which measures about 200 feet wide by 200 feet long, which in my point of view is pretty much, but they use this amount of land to provide enough food for the whole family.
Long story short, birds sing instinctively and behind each song of a bird, there is the instinct for survival.