•About this Yokai•
Rengidori - "れんぎどり（擂木鳥)"
A Tsukumogami (Haunted Antique) of an old Wooden Pestle, which has been freed from its Mortar! it Soars away with wings! [More commonly bird wings: but occasionally a Bats!] This Yokai appears in a lot of Edo period toys and board games! Aside from that I believe that I read somewhere that they're specifically made of camellia wood.
See also: Furutsubaki No Rei