Rodents are significant agricultural pests in Australia and internationally. Recent proposals to address the Australian problems by allowing farmers to obtain desexed cats, at tax-deductible cost, to control rodents on their properties are, superficially, attractive, especially given enthusiastic endorsement from 15 dairy farmers from nine properties in Queensland and New South Wales. We argue that far stronger evidence is required to take this solution seriously, and for broader ethical and regulatory reasons, it may not be appropriate even if evidence was forthcoming. Evidence via direct population monitoring or indirect monitoring using bait removal is first needed to show that rodents are effectively suppressed by cats and how many cats are required. Further supportive evidence could come from monitoring the diets of cats using techniques such as analysis of stomach contents or scats, collar-mounted video cameras, or stable isotope analysis of cat tissues such as whiskers. These techniques would also quantify any predation by farm cats on wildlife. Population monitoring of cats would confirm whether there is unwanted immigration of cats into the farm cat population, while economic modeling could compare the costs of a farm cat program to other rodent control options. In the absence of such data, promotion of cats as a solution to rodent issues on Australian farms remains unsubstantiated and is premature.
Calver et al. (Thu,) studied this question.