If you aren't big into treats (neither am I, I don't want them to fill up on goodies), you might want to try freeze-dried meats. So far we've had great luck with Beefeaters Nature's One Chicken Breast. The chunks are soft enough to peel into small segments, so you can give cats little bits at a time. They're thrilled to get those slivers of chicken!
the3rdnae, motion sensor sprinkles would be a great idea except . . . . we're on a multiple acre site. These are either barn cats sauntering across the road OR a neighbor's pets, ditto.The latter is more likely. We'd have to stretch hoses across the lawn in three places and leave them there, something that's not good for either lawn nor hoses. Besides, there are all the deer, woodchucks, rabbits, birds, endless array of critters that come sauntering hither and thither across the grass.
We don't feed treats. The calming treats I just bought - both cats eat them but not with wild enthusiasm. I'll have to look next time I'm at Pet-Valu or Pet-smart or whatever.
But perhaps even a sheet of cardboard to quickly block the view might help.
However this is a great improvement and it's just been a week. Will try again tomorrow but tonight we're both too tired to stand sentry while the boys eat.
Stay tuned for future developments!
If you have to temporarily block the windows, by all means. I hope it works out for you! It's important that they have windows to observe the world through, so I hope it isn't necessary to block all of them. Watching the goings-on in the world outside is actually necessary for a cat's mental health: you don't want to inadvertently create new problems in place of the ones you're trying to fix.
I know you've got strong feelings on the subject, but l'll just say that it won't hurt anyone to divert animal traffic away from problem areas. You have a spacious yard from the sound of it, so you aren't going to put a crimp in the critters' style by deterring outside cats from traveling near the windows. Animals survive in the wild because they're adaptable...they would alter their usual routes through your yard quick as a wink. Not to mention, you wouldn't have to leave any deterrents in place for very long. Those outside cats are quick learners. Just a little food for thought.
Best of luck!