It is very likely that that was the case RCF - and I very much remember thinking that the male we saw in the spring of 2010 was Zeus. Nice to know that he was driven off rather than meeting a more tragic end that's for sure. And interestingly, he has a habit of sabbaticals - 2010 would be his third I believe - should have called him "Houdini" he disappears and reappears so much!
Zeus was hatched in Brandon in 1995, but didn't nest until 2002, could be he was off nesting somewhere else and took over in Brandon when his father Mufasa didn't return. So far as we know, Alice (Grand Forks) is Zeus' fourth mate after Ita (Regina), Holly (Fargo) and Hurricane (Radisson), and other than perhaps Ita, he taught his ladies what to do and did a good job of it, so if he wants to take a year off now and then, more power to him. He is as of this year, our oldest breeding peregrine - not our oldest however, we did have a male that fledged from Winnipeg in 1986, spent his life doing something somewhere and then died in 2004 (18 years of age) only a couple/few kilometres from where he was released.
As for this year, we think he was here in Winnipeg with Alice, I remember thinking her boyfriend looked like one of the "old" birds (Phoebe, T-Rex, Trey, Cowboy). Could be why he didn't take a stab at the McKenzie Seeds site - he didn't get to Brandon until the end of May/beginning of June, by that point the Brandon chicks were hatching and both Hurricane & Brooklyn were definitely hopped up on hormones. Also, Alice started nesting not long after, so Zeus and Alice didn't waste any time once they arrived - they just found a spot (not ideal as it turned out but not too too bad) and set about what he does best and what she could be very good at - she's a smart bird from what I've seen over the last couple of years and I suspect (knock on wood) that we will see more of her - not a bad thing by any stretch of the imagination!