A birdie with a yellow bill

Robert Louis Stevenson???

Jeesh!!! It *was RLS. I thunk it were some Hoosier.

Attual® the way I first hearn it were:

A birdie with a yaller bill
Hop upon my windie sill
He squint an shine his eye an said
Ain't you shamed you sleepyhead?

from the lips of Albert Alligator.