Research Update: Preventing Predation of Endangered Black-footed Ferrets

Black-footed ferrets are one of the most endangered mammals in the world and their recovery efforts include a multi-agency captive breeding and reintroduction program. From 1991 to 2010, more than 3,000 captive-reared ferrets were reintroduced at 19 sites across North America. The captive-breeding program has successfully saved ferrets from extinction, but maintaining the captive population and producing kits for reintroduction is expensive. Furthermore, survival rates of captive-reared ferrets are lower than those of wild-born kits.

In an effort to help boost the survival of wild-born black-footed ferrets, scientists with the USDA-APHIS National Wildlife Research Center, the U.S. Fish and Wildlife Service, and the University of Montana recently tested the effectiveness and feasibility of electric fencing to protect young ferrets from coyote predation at the UL Bend National Wildlife Refuge in Montana.

Researchers fenced portions of two prairie dog colonies within the wildlife refuge in order to exclude coyotes from areas inhabited by adult female ferrets and their litters. Results showed the electric fencing was an effective tool for reducing coyote activity in the study area and researchers observed a 22 percent higher survival rate for ferret kits living in protected areas versus unprotected areas. However, the fencing was not perfect and coyotes were found inside the fenced area on three occasions.

The cost for the fencing and its installation were approximately $7,200 per mile. Maintenance and monitoring costs for 2 months were an additional $1,025 per mile. Based on these numbers, researchers estimate that a 20–30 percent increase in the survival rate of wild-born kits would cost around $4,500 per ferret kit over 10 years. That cost drops to around $2,100 per ferret kit, if monitoring is done using volunteers and donated or borrowed vehicles. This study provides decisionmakers with valuable information for comparing the costs of breeding ferrets in captivity versus improving the survival of existing wild-born ferrets.