Factors Associated with Highway Mortality of White-Tailed Deer

During 18 months 874 white-tailed deer (Odocoileus virginianus) were killed by vehicles on the 313-mile (500-km) length of Pennsylvania Interstate 80. Male and female mortality was generally similar; however, during December male mortality decreased while female mortality increased and during May and June there was an unexpected and unexplained increase in male mortality while female mortality remained essentially stable. The location of highway fencing was the most significant of the factors studied. Generally, high deer mortality occurred where the fence was located at the edge of a wooded area or within 25 yd (23 m) of the nearest wooded area. The lowest deer mortality occurred where the fence was located over 25 yd from the nearest wooded area. Low mortality also occurred where the fence was located within the woods. The effect of vegetation on deer mortality was significant only where fencing was absent.