See it there?
Can you hear it through the picture? It's hummmmmmming.
Holy hell. This freaked me out more than I can tell you. Chris assures me it's a group of bees, that there is no structure underneath. He assures me they'll be gone by the morning. I don't believe him one iota so first thing tomorrow morning I'll be checking and if it's still there - and it will be - I'm calling Mr. Professional Bee Remover Guy to come take care of it.
Oh, and Chris got stung as he was walking back into the house from inspecting the tree and blabbering about how it was fine as long as we leave it alone. Uh huh.