I love cats, but I was sorry to hear about the bird. I used to put a little bell around my cats' collars so they could not sneak up on birds, but this reduces their effectiveness against rodents. We don’t have rats here, though. My province, Alberta, Canada, is said to be the largest rat free land mass in the world. We have rat patrol at the provincial borders. People usually think I am joking about that, but, strangely, it is a real thing!