This article is super disappointing in that, despite the headline, they didn't manage to talk to a single person who isn't pro-TNR, or an ecologist, or anyone who has studied TNR scientifically.

TNR is becoming more popular not because it actually solves the problem with feral cats, but because it is easy and cheap for local governments and looks good to voters. Euthanasia programs are political suicide. But now with TNR, if you've got feral cats on your property, pooping toxoplasmosis into your vegetables, they are officially now your problem. SPCA/BARCS won't take them, they will only spay/neuter/vacc them and dump them back outside. And that's if you trap them and bring them in yourself.

TNR relies on volunteer labor, so of course it's going to fail, but even in studies of managed colonies it didn't result in population decline because there are too many cats roaming around and getting dumped. Allowing and tacitly encouraging feral cat colonies encourages shitheads to dump their cats because they can assume it will survive like all of the other ferals.

Euthanasia is more humane than TNR. TNR is catch->anaesthetize->neuter->dump immediately back into the world with minimal or no post-surgical care->die horribly (generally very young). Euthanasia is just trap->anaesthetize->euthanize. Less stress for the animal and much less stress on wildlife populations whose lives also need to be considered.