After watching the local A&P removal a birds nest from inside the wing of a C172 during an annual inspection, a plane that had not been flown for three years, steps where taken to discourage birds or vermin from residing inside the Xenos wings. Purchased several 3 and 4" mailing tube plugs and test fit into the lightening holes in the inboard and outboard fore and aft wing ribs. Caps have a slight taper and ribbing that locks nicely into the holes. Will purchase additional and trying trimming a couple to clear aileron pushrods and spoiler control wires.