I never thought I'd be upvoting a BuzzFeed article on Hacker News, but this was surprisingly well-written and interesting. The best part:

"Since litter training is the only thing separating the sanctuary’s residents from their feral cousins, one might wonder about logistics of supplying all that kitty litter. Where do all these cats go to shit?

Here, Ellison’s predecessors have unknowingly left behind a solution: the common but non-native Cook Island pines, which were imported to the island in 1911 by naturalist and rancher George Munro after he noticed the fog condensing on the stubby needles of the lone pine outside his cabin and saw an opportunity to solve the island’s fresh-water problem. Fast-forward a hundred years and it turns out those needles, once dried out and mulched in a woodchipper, are also great for soaking up cat piss."