In my view Mozart and Vivaldi were both birders.  You can find some
examples in their compositions.  Below you will find a beautiful story
from Luis Baptiste, perhaps known by some of you (do you Bill?).

At 27 of May in 1784, Mozart bought a starling in an animal shop.  He
loved the little animal.  He taught the bird to sing a theme from his
Pianoconcerto in G (KV 453) and made notes about his own melody and the
way the starling imitated this.  The tiny bird did not catch the right
melody completely but Mozart was delighted.  After three years his little
friend died and Mozart was inconsolable.  He buried him with his friends
all wearing black cloths.  Mozart composed an Ode to a starling.  It was
the"birth" of Ein Musikalisches Spass KV 522.  This composition was a
riddle for many years for our musicologists.  You will find the little
starling in this funny composition.

Birds like Starlings have two sets of vocal cords!  One set at the
left and one at the right, and together you call it Syrinx (remember the
wonderful flute solo of Debussy).  They are able to sing to different
songs in one, even in counterpoint (giggle) Bach would have liked that!
A starling is able to imitate a flycatcher and a sea-gull in one song.
It proofs how underdeveloped we are, don't you think.  Oh, how I would
love to sing in counterpoint on my own!  But unfortunately the only thing
I can do and will do is giving a lecture for the members of the Society of
Fieldbiology called KNNV in the Netherlands.  It's about the similarities
etc.  of birdsongs and music.  And it's also about the composers, who
used one way or the other sounds of birds in their compositions.  So I'm
collecting all kind of stories, poems or scientific essays about this
subject.  And of course I would love to hear them from you privately.
Perhaps others listers would also like to hear about the Composers, who
incorporated birdsongs in their works too.  Hopefully awaiting for your
information,

Henny