She had her operation on Tuesday and seemed fine. Wednesday she seemed a bit under the weather but nothing unusual - the day after the surgery is usually hard. But today she seemed really lethargic and sick. She was virtually unresponsive when we went to check on her. We rushed her to the SPCA and left her with them for assessment. But apparently shortly after we left she passed away. They think that likely she had some kind of underlying condition - life is hard, after all, on a wild cat.
It's the challenging part of the trap/neuter/release program. These wild cats can have any number of diseases and immune system weaknesses. They have surgery, and then they are released back to the wild the next day. They are released that early simply because the caretakers (ie us) don't always have the means to care for them post-op. Not everyone has a shed or garage where the cat can recover outside the cage without risking injury to it or the person. So when the cat is released post-op, it can go off and recover well or it can go off and die quietly because some pre-existing weakness means the cat can't recover from the surgery.
There is no way of knowing how many of the TNR cats do survive. But the program is a necessary one because it is the only real way to control the feral cat population. We got Clementine neutered because we believe it is important to keep wild cats from having litter after litter after litter. It's just really so sad that in doing the right thing, we didn't help her.