There is currently a big brouhaha going on between the cat lovers and bird lovers in my town. Seems like each wants to inflict their version of idyllic nature on everybody else. The big argument is "natural" versus "domestic" predators.
I don't put much weight on that argument, because those are the same folks who turn around and tell me I am an "un-natural" influence on the world and want me to stop hunting. I'm not outside the food chain, however, I'm on top of it and intend to stay there.
And nobody can follow the whole problem through. Sure, the cats kill lots of songbirds, but it is the songbirds that cause the cats! Think about it. Look at all the people who go to Sam's Club and buy birdseed in 5 gallon buckets. They give this to the birds, which increases the number of birds.
If they threw hamburger around their backyards they wouldn't be surprised when a cat or two showed up, but they can't make the connection that they are doing the same thing by keeping their back yard full of fresh meat wrapped in feathers. Given this increase in the food supply, the population of feral cats goes up, and when that happens, well shucks, here come the coyotes.
A lot of these people are just too damn dumb to figure out that when you throw a rock in the pond, the ripples go out clear across the lake. When you dump tons of food into the ecosystem, it doesn't just stop with the first critter that eats it. Instead it feeds the birds, cats, coyotes, bigger cats, carrion eaters, mice, worms and bacteria.
So when we shoot feral (or otherwise) cats, we are just part of nature's system. Call it natural or call it what you want. I just think of it as facilitating the transfer of energy down the food chain. I'm not going to eat it, but _something_ sure will.
Bobcat hunters especially should keep this in mind. I've heard it said that the way to clean up on bobcats is to lug a hundred pounds of cracked corn into the area you want to hunt and spread it all around. It will take the birds a few days to figure it out and a few more for the bobcats to learn where the banquet table is. After that, sneak in, call, and take advantage of the situation.