What barrier provides bird-proof doors for warehouses, grain storage areas, and other buildings while allowing easy access for people and equipment?

• A. Commercial plastic strips
• B. Monofilament lines
• C. Visual frightening devices
• D. Propane exploders

Answer: (A)

Strips of hanging plastic curtain doors block birds while still letting people and equipment pass. These commercial plastic strips create a flexible barrier in doorways—when someone or gear moves through, the strips part and then close back together, keeping the doorway effectively sealed for birds and dust but unobstructed for movement. This makes them ideal for warehouses and grain storage where access is frequent but bird entry must be minimized. Other options aren’t door barriers: monofilament lines act as deterrents but don’t provide a passable barrier; visual frightening devices rely on perception rather than a physical barrier; propane exploders are loud deterrents and not a doorway solution.