Possible Clues:

• Use sol to make them resemble blackbirds
• Birds
• European blackbirds
• Airport luggage belts lacking vehicle for fliers
• Common European thrushes
• Louse disturbed by spades flying in the air
• European blackbirds (Var.)
• A louse's flying for them
• Common European thrushes (Var.)
• Lose us among common European thrushes