Don't worry about the birds, they will go back to the tower, this is far from the first time workmen have been on the rooftops around the building. All of our pairs have lots of traffic on rooftops around their nests, its a function of urban nestsites and I have never seen a bird give up on a favoured perch unless its actually removed. He may not be on the tower as much because he doesn't have to defend the nestbox, he isn't as focussed on the tower OR he could be spending more time closer to Hurricane to reaffirm their pair bond - we've seen on a number of sites with failed nests over the last couple of years and it isn't unusual for the pair to start courting each other again - helps to solidify their pair bond. And since they don't have chicks to provide for, as hard as that sounds, Hurricane and Brooklyn get to spend their time replenishing the resources they expended producing/providing for/protecting Mac and Kenzie - they have used up alot of their personal resources this year. When it happened to Trey & Princess in 2008, they were back fast and had three healthy, smart chicks (Ty, Tupper & Vesper) the next year, so its a good bet that is what could happen next year.