Gareth Morgan wants to eradicate cats from New Zealand. His campaign website does a good job in describing the various evils cats perpetrate upon our ridiculously pacifistic native wildlife. But it's missing the first thing I'd have expected in a policy campaign coming from an economist: a cost-benefit analysis.
First, how much consumer surplus is generated by cats? It has to be pretty big. The New Zealand Companion Animal Council claims* that the 48% of NZ households owning at least one cat spend on average $838 per year on their cats. 1.419 million cats at $466 per cat is about $660 million spent on caring for cats. I don't know what the price elasticity of demand for cat ownership is, but aggregate surplus seems awfully likely to be big.
Second, how elastic are wildlife numbers to cats' presence? Cats kill a lot of things; they're awfully murderous. But if they weren't there, would native wildlife rebound, or would the population of other predators expand with the reduction in competition?
Finally, how much value do we really place on native wildlife? Sure, we get some existence value from the birds and lizards that cats eat, and it's nice seeing them and hearing them. But is it enough to trump the consumer surplus that people get from cat ownership? I don't know and neither does Gareth. But I'm not the one wanting to kill all the kittens.** Shouldn't we have to run a cost-benefit analysis before considering kitty genocide?
Gareth does recommend a few potentially useful things, like belling cats. I doubt that the cats who do the most damage would be the ones that are belled, but the proposal at least doesn't seem likely to do much harm. Another option: make your next cat a Persian. Our last one was so ridiculously over-bred*** that she could barely eat kibble, much less do any harm to, well, anything other than furniture, carpets, clothing, and my dignity.
* I have no clue how reliable their survey is.
** Ok, he isn't really saying we should kill them all, just that we should phase them out over time. But, still, I'm pretty sure that every time you drink a Coke, Gareth Morgan kills a kitten.
*** We got her from the Cat Protection League's cattery. Long story there. After we moved to New Zealand, Susan insisted we get a cat. I asked that it please please please not be another long-haired one. She sent me to the bank machine to get cash to pay the Cattery after we'd been looking at a nice short-haired one. When I got back, she'd signed all the paperwork for a defective Persian with a substantial underbite. The cat was lost eight years later consequent to the earthquakes.