Effects of Four-Lane Highways on Desert Kit Fox and Swift Fox: Inferences for the San Joaquin Kit Fox Population

Limited information is available on whether the San Joaquin kit fox (Vulpes macrotis mutica) uses below grade passages. Swift foxes (Vulpes velox) were studied in Colorado and South Dakota and desert kit foxes (Vulpes macrotis arsipus) in California to investigate the movements and crossing behavior of these animals around four-lane highways; this report examines the results of those studies. Four-lane highways generally were not found to be barriers to fox movements. While a small sample size precludes determining optimal crossing structure design for San Joaquin desert kit foxes, some general design principles for wildlife crossings can be determined. The best practice would be to install as many culverts or crossing structures as possible within the San Joaquin desert kit fox range.