I have to disagree with the letter writer who assumes cats reducing the bird population is a major concern.
Very few housecats have the ability to catch one, and many get their prey from injured birds hitting windows. Feral cats are better as it’s their survival, and we all know how the feral population is started: owners not spaying, neutering, dumping their cats, or people getting more than one pet and the other leaves or is left outside ignored.
As she mentions, pesticide use is never good, which is why I like my neighbour’s cats as they keep the rat population away. If she’s lacking songbirds then she has no vegetation in her yard that would interest a songbird. I have lots and have many other birds, including eagles, owls, ravens, turkey vultures, and ospreys. These birds reduce the number of songbirds as well. Raccoons decimate birds more than cats. This is how Mother Nature works.