jess
Falcon leg band
A jess is a short leather strap fastened around each leg of a hawk or falcon, used by falconers to secure the bird to a perch or glove.
The straps typically have rings at the ends for attaching a leash: The falconer checked the jesses before releasing the bird.
The verb to jess means to fit a hawk with these straps. (Capitalized Jess is a given name.)