Possible Clues:

• Marksman gets bird on top of roof
• Someone who swoops in at the last minute to win an eBay auction
• One whose aims are hidden
• Gunman is discontented about missing number six
• One trained to shoot birds, right?
• Tends to shoot one down from a distance in Trim at conference centre
• Marksman put down rook after another bird
• Person taking out second child half-heartedly
• One to criticise smallest cut with little hesitation
• Tends to shoot one down from a distance in Trim conference centre