European Paper Wasp

I have a nest of this species on my fence in the backyard. Today when I was home on my lunch break, I noticed they were mostly out of the nest and on the fence post. I went and got a couple of shots and decided to go back to work. When I came out, I noticed they had shifted to the knot on the fence. Regretting brining my camera back out, I watched them chew on the knot and pass the little wood bits off to other wasps, who then took them to the nest! That would have made a nice little film:(