Be like the bluebird who never is blue,
For he knows from his upbringing what singing can do. ~ Cole Porter, Be Like the Bluebird, 1934
Hadn't planned to post for songtitle, but these lyrics to the song Be Like a Bluebird popped up when looking for a bluebird quote: https://www.youtube.com/watch?v=KYfgBHlbsN0