It was over a week ago that I had to be the hand of mercy at the end of a black-capped chickadee's life after it suffered at the paws of a neighborhood cat. I spoke with the neighbor who owns the animal, expressing my concerns and my wish that the cat was to be kept strictly indoors. While I disagree with their assertion that "no one can keep a cat indoors 100 percent of the time" (I know a fair few responsible, compassionate cat owners who do just that), I appreciate their willingness to do their best to keep the cat secure.
That said, in the past week I've twice seen the cat back in our yard. She may be learning her lesson, however, as she is not lingering and tends to skedaddle quickly as soon as she is spotted. I've seen no further evidence of her predatory instincts, and whenever I do see her I make loud, mean shouts and chase her off right away. She may, perhaps, be learning her lesson about not being welcome in my yard.
I'm going to give it a bit more time, and will likely be speaking to the neighbors again - gently, but with compassion I hope they will share. I will certainly speak with them should I find another dead bird that defies other causes (window strikes, disease, etc.). It is hard, negotiating in this way, for on one hand I want to protect my birds and it is their cat doing the trespassing - against both city and neighborhood laws - yet neighborly is another matter. I'm looking into other deterrent methods, but the mixed reviews motion-detector sprinklers and other devices have aren't promising. Perhaps my scare tactics on the cat will help her learn permanently that she needs to keep away, and I can keep away from less than neighborly conflicts.