What accessory is designed to protect the bird's feet during free-flight?

The correct accessory designed to protect the bird's feet during free-flight is gloves. Falconers use gloves primarily to handle birds of prey safely, but they also serve a secondary purpose of preventing potential injuries to the bird's feet. When a falcon or hawk is in free flight, it is subject to various environmental conditions, including rough or abrasive surfaces, which can harm its feet and talons. The glove provides a protective barrier that helps to insulate the bird's feet from such hazards while allowing the falconer to maintain a secure grip.

In the context of falconry, while other options like 'shields' and 'webbing' may seem semantically related to protection, they are not standard accessories used specifically for the purpose of covering a bird's feet during free-flight. The term 'mantra' does not pertain to any recognized equipment or practice in falconry. Thus, gloves are the established tool for ensuring the safety of a bird's feet during flight activities.