Possible Clues:

• In a heroic fashion
• In intrepid manner
• Fly in a brave way around being deaf, perhaps
• Presumably picking up nothing in fishing lure with plenty of grit?
• Brave enough to fly around without a sound
• Without flinching
• Float around without hearing organs in brave style
• Boldly rush around like Van Gogh?
• With great courage
• Not in terror of being deaf with the fly around