Effects of 4-Lane Highways on
Desert Kit Fox and Swift Fox
Interferences for the San Joaquin Kit Fox Population

This study is investigating the movements and crossing behavior of desert kit foxes and swift foxes in and around 4-lane highways. The goals of this study are to: determine the effects of four-lane highways on desert kit fox and swift fox movements in order to make inferences from these surrogate species for San Joaquin kit foxes; and monitor fox use of existing below-grade passage structures (e.g., culverts, stream undercrossings, bridges, etc.) to identify attributes that facilitate movement through such structures. Specific objectives of the study are:

• Determine if four-lane divided highways inhibit fox movements;
• Quantify fox crossing rates of four-lane highways; and
• Determine where foxes cross four-lane highways, with particular interest in movements under the road via culverts or other passage structure opportunities.

Findings from this investigation will provide management with information to plan and design highway expansion projects with effective below-grade crossings for San Joaquin kit foxes.