Do wildlife passages act as prey-traps?

A number of studies have proposed that wildlife passages beneath roads and railway lines might be exploited by mammalian predators as 'prey-traps' with prey-species being effectively funnelled into areas of high concentration. This proposition has raised the possibility that use of passages by predators may reduce the effectiveness of passages in conserving other forms of wildlife. We review the literature and conclude that evidence for the existence of prey-traps is scant, largely anecdotal and tends to indicate infrequent opportunism rather than the establishment of patterns of recurring predation. Most passage studies record no evidence of predation in or around passages. Conversely, there is some evidence that predator species use different passages than their prey.