In reply to Phil S: Probably worried about egg thieves or something, maybe trying to come across ott to try and put you in a certain level of insecurity (obviously worked to a certain degree).
Wouldn't worry about it, I've come up against something similar from a certain knob sitting high above station before.
Anyway, something I find more interesting, isn'tit wierd that 2 such strong and dominant birds will nest beside each other. I witnessed this the other week and all hell was breaking loose between the 2. Great to watch from the ground but not really a peaceful life for the birds!