Survival and cause-specific mortality of swift fox, Vulpes velox, on crop and range lands in western Kansas

Funding: Kansas Department of Wildlife and Parks

Investigator: Raymond S. Matlack, M. S. Candidate

Supervisor: Philip S. Gipson

Completed: October 1997

Because of reduction in numbers and range of the swift fox (Vulpes velox) the U. S. Fish and Wildlife Service was petitioned to list the species as threatened or endangered under the Endangered Species Act. The petitioner listed reduction of habitat due to agricultural conversion of land as a possible cause of the reductions. However, in western Kansas, swift foxes have been found to make substantial use of crop land throughout the year. The goal of this project is to examine and compare survival and cause-specific mortality of foxes resident on crop land and adjacent range land habitats. Fifty-two adult swift fox were captured and equipped with radio collars, 25 on range land and 27 on crop land during 1994 and 1995. No significant differences were found in survival or apparent cause of death for swift fox between the two habitats. Coyotes and vehicle collisions accounted for 35% (7/20) and 25% (5/20) of swift fox deaths, respectively. In addition, no differences were found for any of the morphological measurements made (ear length, hind foot length, tail length, total length, and body mass) except for body mass. Foxes resident on range land had greater body mass (x=2.27 Kg) than foxes resident on crop land (x=2.11 Kg; n=66, P<0.01).