Richard Bach. The Seagull named Jonathan Livingston (№ 27318)

Jonathan Scagull discovered that boredom and fear and anger are the reasons that a gull's life is so short and with these gone from his thought, he lived a long fine life indeed.
Jonathan understood why so short life gull: eats her boredom, fear and anger, but he forgot about boredom, fear and anger, and lived a long happy life.