U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version



Wildlife Society Bulletin 35(1):32–39; 2011; DOI: 10.1002/wsb.4


U.S. government work.


Mortalities from collisions with vehicles have created concern for the welfare of the San Clemente Island fox (Urocyon littoralis clementae); 1 of only 6 genetically distinct subspecies of island fox. To find possible solutions for minimizing these mortalities, we compared 9 characteristics of roads and roadsides at kill-sites and control-sites to ascertain whether certain features were associated with risk of collisions. We found that kill-sites were positively associated with the volume of traffic, and negatively associated with the distance of motorists’ visibility, which had not been previously identified for island foxes. Additionally, visual obstructions along roadsides (i.e., steep ditches and tall vegetation) showed some evidence of increasing mortalities. We also found that gravel mounds, a possible pseudo-barrier along roadsides, were associated with reduced mortalities. Speeds of vehicles, presence of drainages, cacti, and culverts, and seasonality showed minimal effects on road-kills. Our findings suggest that efforts to reduce mortalities should focus on roads with high volumes of traffic and high amounts of visual obstruction for motorists. Possible methods for reducing road-kills include installing signs and speed bumps on curves of roads, regular mowing of roadsides, constructing gravel-mound barriers along edges of roads, and educating motorists.

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