It is hard saying what I mean on line, I know what I mean but it does not come forth the way I want it to.
Oh I give up . It will not come across right no matter which way I say. so I will just drop the topic.
Oh don't do that - its not a case of "right" or needing to drop the topic - this is exactly what Projects have to deal with when we are trying to assist peregrines in urban locations. And its important information to know and be able to communicate when people ask "why can't you put a nestbox up for them"....
I think I did not state my point well enough. what I mean is that when a peregrine comes from a certain area , in a lot of cases they go back to that area.
Yes and no. Most young peregrines that survive year one, don't come back to their natal areas. Trey didn't, he returned the year after and then continued to return. Ivy didn't either the first year. Lucy, Ivy's sister did, but after her failed nest with Ivy at 2 years of age, she left the area. Obi-Wan from Brandon spent his first year in Winnipeg then dropped off the radar entirely. Madame, Trey's Mom, turned up her less than 12 months after she hatched and never left (she overwintered).
They released last years peregrine and his sense of instinct sent him back to that area. but another one is already there.You have the Trey at your site but he moved over from another site in Winnipeg. You have a male in West winnipeg but it came from Winnipeg. (If I read what you said earlier right.)It is not exactly the same spot, but it came back to Winnipeg.
And birds that have nested in/are nesting in - Grand Forks & Fargo ND, Omaha & Lincoln, Nebraska, Saskatoon, Moose Jaw, Regina, Calgary, Edmonton and of course, Brandon ... and those are just the ones we know about
Of course peregrines are going to wander over from other areas. There's might be full, we do not know. So they wander, thus the peregrine. I know that they will not necessarily go to box becasue it is put there. I have had that explained to me by the biologists here. I also know that if they see a peregrine nesting one year they will try an accommodate it the next year. Thus we have a box at the U of a. They will not always return there either, but a good chance is they do , if possible. they do what pleases them for their own survival.
They tried to create a new nestbox for the TF becasue she liked the Weber building but they were not allowed, by the management. Maybe she would nest there maybe not, but they wanted to give it a try. To make more room for the falcons.
A lot more peregrines are going to the Toronto area,and that is great. It means they are becoming more successful. So maybe an area that they think will appeal to the falcon could be made attractive to them(and I do not mean decorating 
) It might work, it might not , but at least it is there.
Here in Edmonton they put a nest box in a certain area and they never nested there but when a male was forced out of an area last year it went to that nest box. This was all explained to me.
You are exactly right, there is almost no way to predict anything, but Projects like ours, Alberta's, Ontario's, etc, can't just be re-active, we have to be pro-active because we have a limited window of time while the birds are here and the peregrines often have a limited attention span. Peregrine in town on year, put up nestbox and hope bird is back next year and with a fertile receptive companion AND they approve of your nestsite selection skills ... art and a science sometimes ...
Speaking of the science, here are some stats that may be of interest ...
females generally move further than males to breed
- among the population on the Prairies/in the Midwest - 67 females moved on average 345km and 73 males moved 174km to nest
- another study showed 75% of females moved 355km to nest, 75% of males moved 170km to nest
- of 1700 banded chicks in Greenland (from 583 separate nests) - only 35 males and 7 females came back to nest in their natal area(s) - note female mortality is greater which may help to account for fewer females returning
peregrines are very attached to their nestsites once they have them
- females more likely to switch sites than males overall
- in our population - out of 241 territories (over a number of years) 7 birds left territories where they had been unsuccessful (nest failed or mate disappeared), 4 successful birds moved to "better" (more successful) sites and 3 lost territorial disputes but survived
