Found one in North Georgia, Union County, Lake Nottley on the shoreline of Davenport Mountain, in about six inches of water. I was lamenting to my then wife that her sister's boyfriend could find an arrowhead but I couldn't find a thing. Looked down and saw what looked to be the milky colored gills of a dead salamander or newt or something similar. Turned out it was the knapped wing of a small thunderbird. Beautiful piece! Wondered for the past 32 years now who lost it, when, where it had come from, etc. I made a small thin deerskin bag for it (about 1 3/8 inches wing tip to wing tip. I've carried it ever since. Have never seen another that had such fine craftsmanship. Oddly enough (or perhaps not odd at all, actually), it has opened a few doors for me though it never been shown to anyone except in the bag (the bag has now formed itself around the eagle and the definition is easily seen).
I have a clay (monolithic, the bowl and stem are one piece) frog effigy pipe. Came to me in a rather interesting (almost said unusual) way as well.
Stay well.
Jim aka kiltiemon