Earlier quoted context omitted.
Because there's a real danger of losing some of these bird species, and absolutely zero danger of losing domestic cats as a species?
Let's do this. And when we're done killing all the cats and the rat problem becomes worse and somehow the birds don't seem to return to the filthy and noisy concrete jungle with no trees we can just pretend it never happened.
Cats usually won't tackle rats, this is even mentioned in the article.