Finally get a chance to tell this story. One time years ago I was at a fly fishing shop hanging around when a dude came in trying to sell a box of beautifully tied traditional salmon flies. He said that they were made from exotic materials including eagle feathers, blue heron feathers, tiger fur, and polar bear hair, some others. The shop owner immediately turned him away and then before leaving he offered instead to buy any exotic materials the fly shop owner might have around.
The three of us who were there in the shop figured it seemed like a sting attempt and the guy was likely some kind of federal wildlife law enforcement.
So, apparently there are some collectors of fly fishing flies that traffic in banned animal parts.