To through another thought among the pigeons ... incubation for ravens is 20-25 days. First egg was laid on April 12 - so had the original nest stayed in place the peregrines would be desperate to nest (nesting approx 3-4 weeks after returning) right about the time that the eggs were due to hatch. So George & Weezie would be desperate to keep their chicks (hatched and/or pending) and the peregrines would be just as desperate to get in the box. If the peregrines won, George and/or Weezie could have been badly injured/killed and their chicks dead/eggs discarded before hatching. If the peregrines were injured or killed, a loss of a nest for this year and a breeding pair (with new genes from our project) lost to the Alberta population and the Canadian population.
George & Weezie will make great parents based on their stubborness (perhaps not so good in terms of survival instinct but that's supposition at this point), but for the sake of all the birds involved, I really do wish they would take the hint.