Squirrels (?) in my Owl Box

In my last post I mentioned my owl box.  This was originally designed with Tawny Owls in mind.  Its situated approx 30ft up a conifer tree on the edge of woodland which contains many Tawny owls.  Easy I thought... make the habitat, and they'll move in.  Wrong!

Last year a family of Great Tits moved in and I had to add a cover to the Owl-sized entrance hole so that only my great tits could get in.  We had a competing squirrel who I thought would put off the Great Tits somewhat.  Once these chick fledged, I converted it back to the larger entrance hole, and promptly forgot about it as work stuff too priority.

This was my first camera-equipped nest box and it has a roof-mounted ccd-type analogue camera.  The box is approx 1x1x1 ft in dimensions.  Camera image quality started off good, but has gradually deteriorated.  I'm not sure what went wrong, whether its a combination of the 30ft AV cable run, or the subsequent 150ft wireless transmission over a crowded 2.4Hz frequency, or a dodgy camera, but because of this I have not checked it for several months - plus the PC with the motion capture software suffered a hard drive failure which I have only just got around to fixing.

I turned it all back on this afternoon expecting to get a blue screen, but there is some vestige of signal... and I have a new occupant!  All I can see through the white noise is a fair few small leafy twigs, with "something" moving about   Does not look very much like a small bird nest.

At this stage its not at all clear, but I suspect I may have bad case of squirrel.  I suppose they need somewhere to nest too, so I wont begrudge them their squatters rights.

If I can clear up the video a bit I'll post some if its good enough.

Not a nest of a small bird....