How birds tweet

These days when you hear the word "tweet" people only think of posting things on the social media "Twitter.  Please remember that the word actually refers to the sweet singing sounds that birds make !
Anyone who watches birds knows that they have their "signature" tweets. Listening to the sound, the notes and the length of the tweet, ornithologists (scientists who study birds) can tell a lot about the birds. One very interesting question has always remained: how do these little creatures learn to tweet so perfectly ? For instance adult zebra finches twitter one short sequence of notes flawlessly, over and over. How do they perfect their signature tweets? 
Recent studies by scientists has shown that it has to do with chemicals. A chemical signal in the brain apparently dips when they make mistakes, and that same signal spikes when they get it right. The brain chemical dopamine determines all this.
According to a scientist, a bird learning to sing is a lot like a baby learning to talk. A baby bird starts off by babbling. It sings cascades of different notes that don’t make a lot of sense.  The father usually tutors in the case of zebra finches, and gradually the babble becomes a copy of the song taught by the father.
Dopamine is a neurotransmitter — a chemical that transmits messages in the brain. It moves a signal from one nerve cell in the brain to another. A schematic of dopamine processing in a synapse (gap between neurons) is shown in the picture.
The researchers inserted tiny recording wires into the birds’ brains.  While the birds were singing, and listening to themselves apparently make mistakes, scientists observed their brain cells. That is how they found the dopamine effect that reinforces a bird's learning.
Now scientists are working on the hypothesis that there might be a dopamine effect in learning for other animals as well.