Apparently the American Bird Conservancy spies have infiltrated every TNR feral cat colony in the US. The spies each have a clicker counter (made to look like a rhinestone cat collar) to notify HQ about every bird that is killed by a TNR cat. And that count is accurate because you know, there is a code of honor among TNR cats about the birds they kill. The TNR Prey-O-Meter at HQ is about to go into overload, therefore the American Bird Conservancy has pronounced:
[A] feral cat management program called trap, neuter, and release is failing to substantially reduce cat numbers and is contributing to the deaths of millions of birds each year, including endangered species.
To publicize how rilly-super-real their numbers are, they even made a little video.
Debunking here. No Kill Advocacy Center has an informative pdf on TNR here.