The hack box is similar to a natural eyrie. It contains a gravel-covered ledge five feet long and four feet deep, usually placed at the top of a tall cliff. It has bars on the front to protect the youngsters from predators like raccoons, martins, and foxes. There is a hatch where attendants can covertly drop in food to the falcons. Falcons are held in the hack box for about one week until they reach their normal fledging age of about six weeks old. The box is opened allowing the birds to fledge or fly for the first time. Two or three attendants observe the falcons constantly during daylight hours and continue to provide food for the birds at the hack box without the falcons knowledge. It takes about six weeks for young falcons to become proficient at catching prey, and thereby independent from the hack site. (Wild falcons fledging from nest sites in the wild also become independent of their parents in about six weeks time.)