Which of the following are passive bird control measures?

• A. Grass height management, managing reforested areas, controlling drainage, fencing
• B. Pyrotechnics, Bioacoustics, Gas Cannons, Falcons
• C. ATV driving near field
• D. Bird observation and record-keeping

Answer: (A)

Passive bird control relies on changing the environment so birds have less reason to gather or settle there, without ongoing disturbance or the use of devices. Grass height management, managing reforested areas, controlling drainage, and fencing all fit this idea because they reduce habitat suitability in a lasting way: altering ground cover or vegetation structure makes roosting or feeding less attractive, and fencing physically limits access. These are preventive, long-term adjustments that work without continuous action.

By contrast, the other options involve active deterrents or monitoring. Pyrotechnics, bioacoustics, gas cannons, and falcons require ongoing deployment to create fear or disruption. Driving an ATV near the field is an immediate disturbance used to scare birds. Bird observation and record-keeping, while important, is monitoring and does not directly deter birds.