The Fox and the Crow. A need to update pest control strategies.

The recent discovery that cats and mustelids can be infected by SARS-CoV-2 may raise the question of monitoring domestic, feral and wild populations of such animals, as an adjunct to the elimination of COVID-19 in humans. Emergency solutions might consider large scale control of these animals in the wild. However, looking at science recently published on native vertebrate pest control reveals first that usual controls do not succeed in reducing animal numbers and associated damages, second that controlling can be counter-productive in increasing the infectious risks for humans and livestock. The examples of red fox and corvids are detailed in a European context, illustrating the urgent need for an ethical evaluation of ecological and economic costs and benefits of pest control strategies. A complete scientific evaluation process must be implemented and up-dated regularly, to be organized in four major steps, once the aim of the control strategy has been defined: (1) evaluating damages/risks caused by the animals, to be balanced with the ecosystem services they may provide, also in terms of economic costs; (2) unravelling spatial and temporal population dynamics of target animals to identify, if any, optimal control scenarios - which could be done within an adaptive management framework; (3) estimating the economic costs of implementing those optimal control scenarios, to be compared to the economic costs of damages/diseases; (4) finally evaluating how the control strategy reached its aims. A modern fable of the Fox and the Crow should deliver a timely moral for an ethical, ecological and economical appraisal of pest control strategies in Europe.