Well, Animal Control told me i can trap the cat if it comes on my property and take it there. When the owners come to pick it up they will have to pay a boarding fee of $12 per day. If the animal is not licensed, they will have to get a valid rabies vaccination, pay to register the cat, and possibly face penalty charges for not having it licensed.
The last thing i want to do is subject this poor cat to the stress of being trapped, hauled off to Animal Control, and exposing it to diseases from other cats. But i'm going to have to do this as a last resort. Perhaps if the owners are inconvenienced enough and have to pay enough, they will make a more concerted effort to keep their animals on their own property, or in their house.
Anyhow, after i get the final vet bill from for my bird's broken beak, i'll send it along to them with a note telling them that i will be trapping their cats if i find them on my property. Heck, i can just pick the cats up and put them in a carrier. i will also tell them that i will notify them if and when i have taken their cats to Animal Control, so they can go retrieve them. Hopefully they will see i'm not trying to be malicious, just protecting my pets.