If there are no trees about, wedge tailed eagles are quite happy to make a nest on top of telegraph/power poles out in the bush. Otherwise they seem to like a bare branch to perch on for surveillance purposes. We get nankeen kestrels here too, but only see them hovering over the paddocks when looking for prey. Elsewhere I've seen them on power lines doing their obs.
Owls like natural holes in trees, or abandoned nests, so leaving an old tree standing rather than turning it into
firewood might be the go.
They are all such special birds that they need all the help they can get. Watch out for rodent baits that use an anticoagulent - it can pass on to birds through the little corpses.
Also:https://permies.com/t/207474/wildlife/attract-birds-prey-backyards
and once there, there's several other useful links.