To return to the original topic, I have been informed by someone who I would consider an expert, that Long-eared Owls generally do not prey on the smaller owls, except under extreme conditions when their normal rodent food is scarce: Amherst Island this winter is a perfect example where voles are plentiful and all the owls seem to be co-existing quite happily.
I would agree with one of the previous respondents that the best strategy for finding owls is to find a relatively small grove of evergreens and search that---- finding owls, particularly Saw-whets and Boreal, in large areas of habitat is very difficult as these smaller owls do not flush if you are near them so one has to be very lucky, and sharp-eyed, to find them.
The strategy I use in the winter is basically just to scan carefully and slowly every tree--it is time-consuming and tiring but also exciting and suspenseful as one never lknows when one will hit the jackpot. Quite often the chase is just as enjoyable as the eventual find.