Possible Clues:

• Marksman
• Deadeye
• Expert marksman
• Annie Oakley, for one
• I'm very good at firing cheats - by implication, a wise old bird?
• Sucker taken in by fraud is skilled marksman
• Marksman notes signal to begin, perhaps
• Marksman pointed gun?
• Someone with gun notes owl?
• Marksman taking notes on owl