Mule deer undertake some of the longest land migrations of any terrestrial mammal in North America, and human infrastructure increasingly fragments and blocks these ancient routes.
Mule deer blocked from their seasonal migration routes face a welfare crisis. Deer unable to move to winter ranges may exhaust local food resources and suffer chronic malnutrition. Those attempting to cross high-speed roads face injury and death from vehicle collision. Deer that successfully cross but are cut off from return routes may become isolated from their herd. The physical and psychological costs of navigating fragmented landscapes include chronic stress from repeated failed crossing attempts and energy expenditure in searching for passage. Wildlife crossing infrastructure and strategic fencing represent high-value welfare interventions that also reduce vehicle collision deaths and property damage.