Reducing the Cat's Bag

Many people have become seriously concerned about the numbers of small birds, mammals, reptiles and amphibians that are killed by domestic cats. In some parts of the world (notably Australia) the owners of domestic cats are required to fit them with bells. A new study reported in the journal Biological Conservation by Prof Mike Calver and Sandra Thomas of Murdoch University (http://www.catgoods.com/autrial.html) has looked at the effects of fitting 56 'serial offender' cats in Perth, Western Australia with clip on, brightly coloured bibs (CatBib). The bibs are said to not prevent the wearer grooming, running or eating but do limit the cat's proficiency in stalking and pouncing. The cat's owners were asked to keep a log of the dead animals brought back by their pets and reported that the three week 'bag' in the absence of the bibs included 65 birds, 164 mammals (mainly rats, mice and bats), as well as 67 reptiles and amphibians. When the cats were fitted with the bibs in the last 3 weeks of the study, 81% failed to catch birds, 45% took no mammals and 33% failed to land a reptile or amphibian. The study suggested that the bibs cut bird deaths by up to 67%. The authors did look at CatBibs of differing colours and the effect of augmenting the device with a bell. One might question the methodology in terms of its ability to deliver accurate measures of the numbers of small vertebrates killed, injured or simply disturbed by the cats. If anything, the recorded numbers are likely to be underestimates. It is even possible that, with greater passage of time, these highly effective predators will find ways of minimising the effectiveness of their bibs. The study does, however, add weight to the view that domestic (as well as feral) cats are serious challenges to the survival of a wide range of small vertebrate species and that some relatively simple and humane devices can ameliorate the actions of these predators.