In reply to drsdave:
I unknowingly set off up Roof Route today, following my mate's lead of Root Route, and got a bit of a nasty shock just as I was thinking about getting some gear in the roof - heard a rustling sound, saw the owl in the cave, ducked and saw it fly by me. No idea if there was a nest in there as I downclimbed pretty quickly in a state of bewilderment, but it would appear that the cave is still occupied!