What is the term used for the leather straps fastened to a trained hawk's legs?

The term for the leather straps fastened to a trained hawk's legs is jesses. Jesses are essential tools in falconry, as they help to secure the bird and make it easier for the falconer to manage the hawk during training and hunting sessions.

Jesses are typically made from leather and provide a means for attaching a leash or other equipment to the bird, thereby facilitating handling and control. They also allow for the hawk's mobility while ensuring safety during flights.

Other options, while related to falconry, serve different purposes. A leash is used to tether the bird to the falconer when it is on the ground. Hoods are devices that cover the bird's head, serving to keep them calm and reduce distractions. Swivels are connections that allow the leash to move freely without tangling. Therefore, jesses specifically refer to the leather straps used to secure the hawk's legs.