I've been noticing that even after I go through and tweak the presets on the webcam, about a week later they seem to shift downward. So I went out there today and checked it out 'cause I was a bit worried that the tree itself was shifting! That's a BIG tree next to my garage and it had me worried a bit. Turns out that the piece of wood I used to mount the camera onto the tree has started to rot.
I re-braced it a bit, cleaned the dome inside and out and then redid all the positional presets. I think it looks pretty good right now, but before the winter I'm going to need to pull it down and replace the mount with some thicker pressure-treated wood. It will be down for a day when I do that and I probably should consider replacing the power cord and CAT6 at the same time.
I have to say that I'm pretty amazed that the camera itself has held up for 6+ years, 16 hours a day, changing directions and focus every 3 minutes!