A friend of mine put her hawk in the weathering yard at the January, 2007 California Hawking Club meet. At the end of the meet, she put her bird in its traveling box, put box and bird in her vehicle, then went back to collect her ring perch. She discovered that someone else had collected it and disappeared in the meantime. She made sure that the meet organizers knew about the theft at the time.
Perches are bits of hardware that cost between $50 and $300, depending on the design and workmanship. The ring perch she had is nearer the upper end of that scale. A similar unit is available through NorthWoods.
The actual perch is in this photo, on the right:
Well, she is back at the California Hawking Club meet this year, and when she went out to the weathering area, she was surprised to see that her perch was there. Apparently, the falconer with the perch now had purchased it off of eBay, and is chagrined to have bought stolen goods. The CHC is working towards identifying the thief and turning him in. They also have offered to buy her a replacement perch, so things are working out.
She says her hawk also caught a jackrabbit today, with an assist on keeping it from her Jack Russell Terrier.