All of a sudden, the Christmas Tree became interesting to the kittens, and now, they're kind of obsessed with it.
The packages beneath the tree act as steps to the window sill. From the sill, they can reach higher branches, and they can't keep their paws off of it. Mostly they just bat at things, but there were a few birds within their reach that now have a teeth marks in them. Those birds have been moved a little higher up on the tree now.
Everyday, they knock a few ornaments off the tree. The boxes and skirt beneath catch them, so nothing has been broken yet.
I am hoping that soon the tree phase will pass, because monitoring the tree has become a full time job.