Some New Zealand bird conservationists favor cats
From ANIMAL PEOPLE, April 2013:
WELLINGTON, New Zealand––Forty-eight percent of New Zealand households keep cats, the highest rate of cat-keeping in the world, according to the New Zealand Pet Food Manufacturers Association. But prominent New Zealand birders disagree over whether free-roaming pet cats and feral cats have much to do with losses of rare bird species. Economist Gareth Morgan argues that cats should be eradicated from New Zealand through universal sterilization and non-replacement. New Zealand Post science columnist and ornithologist Bob Brockie, no friend of non-native wildlife, advocates the use of the pesticide Compound 1080 to kill brush possums. But getting rid of cats, Brockie recently argued, would be a mistake. “Mike Fitzgerald, John Flux and the late John Gibb, all former population biologists in the now-defunct Department of Scientific and Industrial Research, spent decades investigating feral cats, rats and rabbits, and none would agree with Dr. Morgan’s views,” Brockie wrote. “Setting thousands of traps, Fitzgerald calculated the number of cats and rats in the Orongorongo Valley for 23 years. The cats held the rat numbers in check for years but when cat numbers fell, the rat population shot up. The cats also held the riverbed rabbits in check and their population also shot up when the cats disappeared. “Flux logged everything his cat brought to his Melling house for 17 years. The cat brought home 53 native birds and 151 foreign birds. More to the point, the cat killed 63 rats, 221 mice, 35 rabbits, and two weasels. Rats and weasels are much more effective predators than ground-based cats,” Brockie explained, “as they climb trees to eat birds’ eggs and chicks in the nest, and also eat the flowers, fruit, berries and seed before the birds can eat them. “In a two-year trial in the Wairarapa in the 1960s,” Brockie continued, “Gibb persuaded the pest destruction board to stop shooting rabbits on 1,200 hectares of hill pasture and scrub for three years. At the end of that time there were fewer rabbits there than on the adjacent shot-over land,” because of increased cat predation. Said Flux, “The thing to do is to get rid of rats and mice first and work back up. Rats are the major problem and not anything else,” Flux told the Dominion Post, suggesting that a cat who kills a rat has helped birds on balance, even if the cat also kills 10 birds.