They are beautiful and majestic. I just wish they would stick to rabbits, digger squirrels, and other land based animals. Don't like to see other birds getting attacked and eaten.
I love such birds, gorgeous species, but if it's the hawk or my Perjo I wouldn't hesitate and whatever happened to the hawk happens to the hawk. My dreamhouse in my neck of the woods is on the edge of the Metroparks. It has a huge second level deck that would be incredible place for a permanent outdoor cage. BUT I would probably make it a double enclosure just b/c of the fact it sits on the edge of a mini wilderness with such hazards.
Since you are also in the Great White North, I would recommend that you look at South facing dream house, glass face (decks) to take full advantage of the October to April Sun Light!
Just to add a bit of a disclaimer here; Most States have Laws in place that provide 'protection' for 'Hunting Birds' including Red Tail Hawks and of course Eagles, etc... The heavy use of DDT had caused the near full loss of near all of that group of Birds in the 1950's, 60's and early 70's. Those Laws are still in place and although I 'fully' understand your position, take care to only do what is needed to save your Parrot. Now that the disclaimer is in place, we are all much safer!