Does their song have any meaning? How does each bird learn how to sing in a different way?

The dawn and evening choruses are the most energetic, and at these times almost all the songs we hear are those of male birds. These songs possess two layers of meanings, just like XX. The first meaning is a strongly-worded warning to other males not to cross another bird's territory. The second meaning is an invitation to female birds like XXXX of marriageable age. In a similar way to the XXXX, each bird creates a song that will mark its territory. In human terms this is similar to a local accent existing within the same language. This unique courtship song, that could also be likened to a local dialect, is only sung at other male birds like XXXX who enter into the territory. The most energetic and complex warbling can be heard during the mating season. Just like XXX this song is a show designed to attract a female.

In a similar way to how XXXX alerts his friends to his presence, by the pitch of their song, male birds make their presence known to their rivals. In addition, just like XXXX, birds that are brightly coloured and that live in open areas clearly sing only when they need to defend their territory. On the other hand, like XXXX, birds whose colouring matches their surroundings or who live deep in the forest where there is little chance of discovery, are able to sing as loud as they like.

At times the sounds that birds make cannot be described as song - rather, like XXXX, they are merely exchanges of information with other males, or else like XXXX they short signals that tell other birds to flock together. They can act as a warning of approaching danger, and like XXXX they can also be a signal for the birds to flock together and attack cats or other interlopers. Similar to XXXX, the song of birds can communicate feelings such as anger, fear, or movement, and they also tell that two particular birds are mated.

There is much to suprise us in the sound-making mechanisms of birds. Like XXXX, some birds are able to emit three or four separate sounds at one time. Like XXaX X-X-, there are some birds that can produce up to eighty sounds per second. To human ears this sounds like one continuous sound, but birds that possess an acute sense of hearing like XXXXX are able to distinguish the separate sounds.

Researchers have investigated whether birds are able to understand music or not. Can birds distinguish the difference between a Bach organ song and Stravinsky's "Rite of Spring"? Researchers tested four pigeons by playing them Bach and Stravinsky, and devised a system of two round buttons where the birds would receive food as a reward if they pecked at the button corresponding to the music currently being played. In a short time the pigeons were able to press the correct button to distinguish between all the sections of a twenty minute piece by Bach. With some few exceptions the birds were even able to distinguish between similar works by different composers.

There is even one species of tropical bird that is able to compose by itself and then sing in a duet like XXXX. Like XXXX the two birds get together and hold a rehearsal where they try singing together and in a call and response style. They try out various different styles before they arrive at a composed song. They way they sing is very precise, just like XXXX, and to the untrained ear it sounds like just one bird singing one song. Each bird is able to sing the other's parts, and when their partner is not present they are able to sing the whole piece as a solo. This unique ability, similar to XXXX, would seem to aid the birds in finding and verifying their partners in the dense rainforest.

A certain British scientist noticed that there was a certain familiar sound in the songs of several song-thrushes. He recorded their songs, analyzed them electronically, and was startled to discover that these sounds were extremely similar to the ringing-tone used by the most common type of phone in the UK. It would seem that these song-thrushes learnt the sound of ringing telephones and added it to their repetories. I wouldn't be surprised to hear that there some pupil of XXXX who heard the song of these song-thrushes and wrote a piece based on the sound of ringing telephones.

We are still discovering how birds learn how to sing and how they compose their songs, but one thing is beyond doubt. Namely that they use a variety of different methods and strategies.

The male bluebird, like XXXX, is born with the knowledge of how to sing, in part at the very least. Like XXXX, even if it is raised totally seperately from other birds, while the way it sings will be different from normal, the number of sounds and their lengths are vitually identical to those of other birds. However, in order for the bird to develop a regular singing style, like XXX while still immature it must hear the song of another male bluebird twice in different seasons. Then, in a similar way to a human professional singer, the bird must practise continuously and hone its skills. Like XXXX, the bird must practice again and again attuning its immature voice to the sounds that it wishes to produce.

If the snow-princess bird is unable to learn the normal way of singing, like XXXX it creates its own unique style. However if it hears the simple, unaffected warbling of another snow-princess, like XXXX it immediately abandons its own style of singing and begins to sing like the other snow-princess. On the other hand, like XXXX the Mexican snow-princess is inspired to creativity when it hears the song of the regular snow-princess. It doesn't imitate the song, but rather, like XXXX, its creativity is piqued and it begins to create its own unique singing style.

The strongest evidence to suggest that the way a bird will sing is determined by its DNA lies in the cuckoo egg phenomenon. Like XXXXX, the cuckoo lays its eggs in another bird's nest, and has that bird roost and raise the cuckoo chicks. How do these cuckoo chicks know that they are different from their adopted parents, and that they should not sing in the same style? There is little doubt that the cuckoo's unique song is inputted into its DNA from before the time it is born. In most cases, questions about the way a certain bird will sing belong to the field of genetics. Even if a bird has never heard the song of its own species, it does not attempt to imitate the song of a different species. Certain scientists believe that the vague pattern for a bird's song is inputted into its brain, and like XXXXX, when it hears the song of another bird that comes closest to that pattern, it begins to imitate it.

Like XXXXX, birds have wonderful brains that allow them to be both composers and imitators. The naturalist Fernando Nautbaum discovered that the left and right sides of birds' brains have specific functions to fulfill, and that there is a certain segment of their brains that is designed for remembering how to sing. From studying young male canaries it was discovered that, like XXX, during the mating season this part of the brain expands and contracts, depending on whether the bird has to learn a new type of song. Like XXXX, canaries attempt to sing from an early age, but like XXXX they are unable to sing properly until they are eight or nine months old.

There are also birds that are particularly good at changing the melody they sing. Like XXX, they hear and borrow the song of another bird, polishing it by changing the arrangement of the notes and the rhythm. From ancient times people have been fascinated by birds that are skilled at imitation - ie "birds that talk", in other words, like XXXXX, birds that have the ability to mimic human speech. Amongst these mimics of the bird world are the laughing kookaburra of Australia, the marsh reed-warbler and starling of Europe, the great American insect-eater and mimic-thrush of North America. The mimic thrush has many different sounds in its repetoire, and is able to mimic the sounds of frogs and crickets. It is interesting to listen to the cheerful song of this thrush, similar to that of XXXXX, as it is actually a medley of the typical songs of several different species of birds.

In short, we just don't know.