I wonder if this is slowly changing as values change. In NZ there is a growing movement to eradicate pests to help protect native species. Cats fall on the wrong side of this goal. There have been public calls by high profile individuals to eradicate cats. Maybe someday birds will be seen to greater value than cats down here.
That's a very modern trend. Even if they did 'ban' cats I really doubt anyone would look to eradicate them. We aren't going to see cops raiding people's houses to kill their pets. It will probably take the form of mandatory spay/neuter programs to wipe out the population over a period of several years. The feral cats will be trapped and similarly treated until there are only a very few that need to be actually killed.
I do wonder whether a place like NZ might then have a rat problem. Rats also do real damage to native species, including birds as they eat eggs. Removing a key rat predator inside cities might have repercussions.
We do have a rat problem. There are quite a few predator free areas in NZ which are islands or fenced inland areas. With fenced off areas, more problematic than rats are mice, which can get though truely tiny holes in fences, jump quite high and are hard to control. At least rats can be fenced out more easily. In terms of killing pests, some great equipment has been developed recently. A homegrown CO2 powered ", self resetting trap has impressive functionality and ongoing testing is really promising.
Society has flip-flopped on treating cats as pets or as pests, or even as witch familiars. Call me when people agree to kill dogs, who can wreck native populations a lot worse than cats, if left to breed unchecked on streets.
http://nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10...