Will
A good solution to getting rid of the elder pith, though a bit more work involved compared to turning a length of walnut, which is what I used mainly (I picked up some cheap offcuts from British Hardwoods last year). Some of the wands do actually have feathers as a core, though probably pigeon rather than phoenix. And dragon heartstrings, or perhaps these were rubber bands. And unicorn hair, but perhaps it was horse rather than unicorn. I drilled down from the top of the handle, then inserted the core, then plugged the hole, sometimes to match, sometimes to deliberately contrast.