Favoritos de marlboro_vermont_conservation_ecologist

This one's a mystery for me. Three pictures of a snag on a frozen beaver pond. All the old Pileated holes near the water's surface are jammed with debris. There are light colored twigs which were clipped by a Beaver. There's a close-up and a faraway shot of the stuffed holes. Another pic shows the biggest hole after the stuffing has been taken out. The cavity inside the tree is about 1' wide with lots of debris floating in the unfrozen water inside. Were the holes stuffed to keep the water in the snag unfrozen? Is it an air pocket for a Beaver? Or did someone else put all that in there?