Possible Clues:

• Produce bloomer when penning line for poet
• English poet and artist, d. 1827
• William --, English poet (1757-1827)
• William --, poet (1757-1827)
• Songs of Innocence poet
• Successor to a mere poet
• Book by mere poet
• "M*A*S*H" lieutenant colonel
• He found endangered species fearfully balanced
• 'Tyger! Tyger!' poet