Yeah he wrote in "Can Life Prevail?"
"Not only are fanatical animal protectors friends of the cat, but so is half of the population! Man's relationship with nature has never been more deranged, reckless and hypocritical than it is with the cat: when it comes to defending the cat, many environmentalists turn cunning and deceitful ... And what about the thousands of mawkish pictures of cats in magazines? In August, when the fledgeling flocks of little birds move low in bushes and grassy banks, I have seen a female cat carry a little bird to its autumnal kittens every half hour past my ornithologist's workplace - not a particularly encouraging message about my work. Compared to the cat, the sparrowhawk and the hobby are just amateurs. ... The cat problem is growing all the more serious now that animal protection authorities have passed a new insane resolution: they have decreed that putting a cat down by drowning is illegal. The breeding patterns among domestic cats have long infringed all natural boundaries: each cat now has a lifespan of twenty years, brings forth two broods a year, is fertile under the age of one and knows no natural enemies. Nothing even close this has ever before been observed in nature. ... Currently hoardes of cats are posing a severe threat to the conservation of birds and wildlife. A minimum requirement would be for cats to be registered and kept on a tight leash when outside; were any cat to be found slaughtering a protected animal, its owner should be prosecuted. This however is pure utopia - as is always the case with attempts to protect nature that clash with people's ardent desires. ... It is utterly impossible to accommodate cats in northern lands: the cat simply remains a grievance to be rooted out. Sure, cats are linked to some solid traditions, but so are spitting on the floor and tobacco. In any case, cats must be got rid of."
