He he he... We tried the nice little high frequency machine! One problem, we have three dogs in addition to our cats. Oops, guess I was so desperate I missed the obvious.
I tried the motion detector scare crow. That worked for a while until the raccoons realized it was a great way to wet their food before they ate it and the herons became so desensitized I swear they triggered it intentionally to take a nice bath so they could preen themselves better. It did keep the cats away but only for as long as it took them to figure out how to avoid the stream of water. Cats are crafty.
Wesley, sometimes you just gotta give in and surrender. If I admitted to all the devices and natural pest deterrents I purchased to try to deter them, you would be on the floor holding your ribs while begging me to stop before you seized up from laughter. My husband just fenced in the area with metal stakes and chicken wire and I ordered netting on line which I should receive within the next few days and I am enclosing the area entirely. I give up, the critters win.
Please don't think I'm nuts for liking the squirrels. I'm all for gray squirrel stew, hasenpfeffer, and venison stakes as I do realize that even native species of animals can get out of control given the right conditions. I know the squirrels are out of control here (rabbits and deer too) but I have a Short Eared Owl, a Barred Owl, a Red Shouldered Hawk, and a few Red Tailed Hawks that hang out from time to time and scope the area. If I eliminate the squirrels, I eliminate the Raptors that depend upon them for a food source. I used to have several Screech Owls and one pair of Wood Ducks. A few years ago the English House Sparrows got to them and annihilated their nestlings and eggs to take over their nest cavities. The adult Screech Owls were killed but I think the Wood Ducks may have survived. I also have Turkey Vultures in the late spring through early fall. I supplement their diet by giving them dispatched English House Sparrows and European Starlings. Other than that, they live off of whatever they can scrounge up. I know this sounds horrible to dispatch those two species of birds but the Raptors are magnificent native birds and additionally, when I remove a pair of breeding English House Sparrows from the environment, I remove their ability to disperse non native seed into wetlands. English House Sparrows and European Starlings are capable of eating Rhamnus cathartica & R. frangula berries, Euonymous alata berries, all Calleryana Pear fruits, as well as many others that the native species of critters do not eat.
I want you to know I really liked your idea about distracting the squirrels so I put out a pile of nice fresh soil today. Gosh darnit! They're over in that pile right now having a free for all. Next year I will pick up an el cheapo kiddie swimming pool and fill it up when the acorns start falling and see if that helps with other plantings. Great idea! Wish I would have thought of distraction a while ago as I am not going to be in a position to fence in every planting over here or the busy body board members of the home owner's association will be knocking on my door with a pink slip to take down the fencing. We are not allowed to have any permanent fencing other than that which is necessary for horses or swimming pools and even then it is one particular type of white fencing, yes white.