M_Boats: Internal Mast Plug

I recently intended to put some foam pipe insulation over the electrical cables inside the mast to keep them from slapping the inside of the mast while at anchor. About 4 feet into the bottom of the mast I ran into something hard. An inspection with a flashlight revealed a bird's nest. However, after removing it a hard plug remained. Is this common (in Montgomery Mast's), or perhaps was this the PO's attempt at a similar fix? Steve Shenkel <>< _/) M17 # 263 Glendale, AZ