An assessment of wildlife road casulties – the potential discrepancy between numbers counted and numbers killed

Abstract. By artificially baiting roads, it is shown that simple counts of wildlife corpses found on roads are severe underestimate of the actual road casualty rate. The death rate can be 12–16 times that observed by simply counting corpses particularly from a moving vehicle. Removal rates depend on a range of factors including species of predator, species of prey, type and topography of road, road traffic, season, time of day and weather conditions. It is suggested that a greater importance should be afforded, than has previously been the case to the “gross” casualty rate rather than accept the “net” number of casualties as an indicator of loss.