Such a really cool idea. Cut the bottle in half. Top half make into scalloped type of cut. Cut hole in the bottom half. Decorate with paints and trim and left over doo dads – just make sure none of it makes noise because it might scare of the birds. Make a loop with thin wire and with two punched holes in the lid (use a push pin or if you want use a very small drill hole. Make the top half go over the bottom half and glue with epoxy or E6000.