A bird is a bird;
you hear its song,
but you cannot seize the notes
to make them continue.
It just is, and is gone,
and you feel the beauty
of its song precisely
because the notes do not wait
for you to analyze them. 
– Alan Watts

Below are photos of a Pacific Wren, Marsh Wren, and House Finch singing with abandon.
Here are links to YouTube videos for listening to each bird’s unique expression.

House Finch: https://www.youtube.com/watch?v=XN33O27CIo4

Marsh Wren: https://www.youtube.com/watch?v=ZoZnS4X89VY

Pacific Wren: https://www.youtube.com/watch?v=A6f1y0MozCI&t=1s