His nickname was “Yardbird,” which evidently is southern slang for chicken – probably because he loved to eat chicken; perhaps because on his way to a gig, the car ran over a chicken and Parker wanted to stop and cook it. (You can go to Google yourself and look all this up.)
The incomparable (thank goodness!) Kenny G said (according to a website): “Charlie Parker would squeak a lot, and that’s why they called him Bird, because his reed would chirp.”
But he was Yardbird first and that devolved into Bird, so Kenny G is wrong – but is he?
A better question than how did Parker earn his nickname is: why did it stick? and as “Bird” rather than “Yardbird?”
The answer is clear: