Summary and evaluation of the kit fox relocation program, Naval Petroleum Reserve No. 1, Kern County, California

In 1988, the U. S. Department of Energy began investigating the relocation of foxes to Naval Petroleum Reserve [number sign]1 (NPR-1) in California. The objective of the study was to develop techniques to reintroduce kit foxes onto NPR-1. Soft reintroduction was proposed, which is not immediately releasing relocated parent animals. The method involved holding relocated foxes in pens during fall and winter and then releasing foxes in spring and summer. Twelve foxes were relocated to NPR-1 and kept in captivity for 131 days before their release in 1989. Twenty-eight foxes were similarly relocated to NPR-1 in 1990. The distance between the release site and the location of death averaged 6.1 miles for adult foxes released in 1989 and 2.7 miles for adult foxes released in 1990. Distance moved was not influenced by sex or age. In 1990, the distance from the release site and the location of death averaged 1.9 miles for foxes released from pens in hilly terrain and 3.5 miles for foxes released from pens in level terrain. Annual survivorship of relocated foxes was 0.03, which was smaller than survivorship of free-ranging foxes. During the year after release, the number of days foxes survived after release averaged 31.9more » and was not influenced by sex, age, or the terrain in which foxes were released. By April 30, 1992, only one released fox was still alive; radio contact with three foxes was lost. One pup reared in captivity in 1989 was found dead 17 days after its released. The ten pups reared in captivity in 1990 were found dead within 17 days after their release. Predation was the main known cause of death of all relocated foxes. Six relocated foxes survived through one breeding season and three relocated foxes survived through two breeding seasons; four of the six foxes were known to have reproduced with free-ranging foxes.« less