Old-Style "Picks" for Noter Playing

The attached "picks" came with a pair of Amburgey dulcimers from the 60s and I assume they were homemade specifically to play them.

They're all made of hardwood (except possibly the biggest) and are stiff, smooth and even slightly polished (through use?). Very different feel, clearly, both in thickness and length. One is similar to a bird feather quill, others more like the stiff noter used by Nettie Presnell. Any ideas about their use?