Ted Williams has a succinct article on the conflict between feral cat management advocates and wildlife issues in the most recent Audubon magazine. I'm sure he's going to take some flack for this, but it had to be said, and Audubon magazine should be commended for wading into the fray--it's a very emotional issue for so many people. But lets just get this out of the way--TNR (trap, neuter, return) is based on junk science. It actually promotes feral cats rather than reduces their number and impact on the environment.
We need a better option to protect birds and other wildlife. Feral cats need to be removed from the environment. If the animal welfare folks don't want these cats to be killed, than they need to foot the bill to have them taken care of on their own properties and be licensed for the killing of wildlife that will take place on these "cat ranches". Sure it will be expensive to set up cat ranches for all these animals. But that's the only way to manage them so that they aren't killing wildlife.
Feral cats should not be roaming around in public. They are a hazard to wildlife and human health.