We used to have a calico in the area who would terrorize my birds. Once I was at the computer, and some sparrows kept flying at my patio door. They were trying to get my attention! I saw the calico had climbed up to the top of the deck where their birdhouse was and she was trying to fish the babies out! I grabbed the water hose, gave her a dousing, and chased her off. She later returned and finished the job--probably after I went to bed. I was so upset that the sparrows had counted on me to save their babies and I failed. I shot that cat with water every time she got near our yard, and she finally quit coming. I now have a birdhouse on top of some thorny roses. It would be a challenge for any cat to bother those birds!