Interstate Highway Road-Killed Animals: A Data Source for Biologists

Analysis of road-killed animals reported by service crews of state road departments could serve as a data source for long-term information on animal populations. Typical data analyzed for a 7-year period for Interstate-80 (I-80) in Nebraska indicated that monthly highs of road-killed animals occurred in May and October. For the nine species analyzed, high frequencies of road-kills apparently were associated with breeding activities and dispersal. Carrion or roadside vegetation also might attract wildlife to roads and increase their vulnerability to highway mortality. Road-killed animals were not significantly correlated with average daily traffic (ADT) on an annual or monthly basis (r = 0.07, P > 0.5 and r = 0.25, 0.5 > P > 0.4, respectively). Annual road-killed animals were significantly correlated (r = 0.92, 0.01 > P > 0.001) with average vehicle speed (AVS). Annual road-killed pheasants (Phasianus colchicus), as well as April road-killed pheasants were significantly correlated (P < 0.01) with spring rural mail carrier surveys of pheasants. Road-kill data may supplement or substitute for existing wildlife census methods, supply information on interactions of two species' populations (e.g., predator-prey) and identify game-crossing areas that might reduce waste of wildlife resources and wildlife-caused vehicle accidents.