I've got a substantially large tree, I believe to be a mulberry tree in my front yard that overhangs the driveway. Every Spring when it fruits, birds hang out in this tree eating the fruit, apparantly every night, because in the morning on a regular basis my car is covered with bird droppings, fruit bird droppings, that almost act like cement getting it off. And I'm convinced they specifically like to camp over and use my my car for target practise! Anyway looking for a solution and wondering if anyone has experience with an electronic ultrasound device for the purpose of repelling birds from a tree, 30-40' tall? I've seen the price range online from $30-500, and while I think the $500 one would be overkill, my impression is that the $30 likely would not be adequate. The situation is that I'd have this mounted on the side of my house, probably 10-15'off the ground, trying to repel birds from a 30' tree 20' from the house. It's only the part of the tree directly ober the driveway I need to cover, but I'm thinking I'd have to get it pointed up to do the job. But possibly prohibitive is that if I want to cover an area 30x20x30' I calculator this to be 18000 cubic feet. The second question, how obtrusive are these type devices? I was hoping for something only the animals could hear. I don't want to run amuck with the neighborhood association, who would not go for an annoying sound generating, strobe light emitting device on the front of my house. The key is that it would have to be unintrusive to the neighbors. If you have experience, looking forward to some advice. Regarding neighbors and a home association, this is what will kill this idea: purchased this product to scare away deer, rabbits and other pests from a garden. The product is well built and suited for outdoor use. There are different frequency settings that correlate to different animals. However, for some people all of the frequencies are audible to the human ear and for some can sound like nails on a chalkboard.