2 woodpecker feathers glued on with thinned tbIII. First the feathers are applied on an adhesive (not too sticky) with the outside, then the bulky quill is cut off (bellyside) beginning from the bottom. The feather is now like a wet noodle, but still on the tape, now apply the glue and put it on where you want it. Trimming the quill helps a lot laying down the whole feather for good connection.
The finished bow is here.