Jess (falconry) the bird, but the width is proportional to leg-length. Traditional jesses are made from a single length of leather, and slits are placed strategically along the jess to allow it to be looped through itself and around the ankle of the bird so that it fits comfortably but securely about and just above what would be the bird's ankle. With Aylmeri jesses, as created by Major Guy Aylmeri, the end of the jess is instead looped through itself repeatedly to form a "button", or knob at one end. The thin, pliable end of the jess is then threaded through an
The Sibley Guide to Bird Life & Behavior The Sibley Guide to Bird Life & Behavior The Sibley Guide to Bird Life & Behavior is a book by David Allen Sibley that shows readers "how birds live and what they do." It is different from most field-identification guides that birdwatchers carry around; rather than help identify birds, it helps watchers gain a deeper understanding of the birds they have already identified. Instead of concentrating on individual species, the book summarizes information for families of birds, presenting "broad patterns" to help readers interpret what they see. The guide includes nearly 800 of Sibley's paintings. The book was first published