In general, parrots inflict the MOST pain/injury to staff members through:

Parrots are known for their strong, sharp beaks, which they use not only for eating but also for communication and interaction. Biting is particularly significant as it can inflict substantial pain and injury to staff members. The force and precision of a parrot's bite can be severe, capable of breaking skin and causing serious discomfort.

While grasping with feet, striking with wings, and pecking can also lead to injuries or discomfort, they typically do not pose as much risk as a full bite. Grasping with feet may lead to bruises or minor injuries, but the strength of a parrot's beak during a bite can result in far more severe consequences. Wing strikes may startle or cause a minor injury, while pecking is often less forceful and usually more playful. Therefore, biting stands out as the most serious form of injury that staff members need to be cautious of when handling parrots.