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North Dakota's

Federally Listed Endangered, Threatened, and Candidate Species – 1995


Black-footed Ferret (Mustela nigripes)

JPG -- species photo gif--species map

Official Status: Endangered
Endangered species are species that are in danger of extinction throughout all or a significant portion of their range. It is unlawful to kill, harm, or harass endangered species.

Listed:
35 Federal Register 8495; June 2, 1970

Historical Status:
Black-footed ferrets once ranged throughout the Great Plains. It has been calculated that if all suitable habitat had been used, as many as 5.6 million black-footed ferrets may have existed in the late 1800's. Populations declined dramatically in the 1900's. The last known population was found at Meeteetse, Wyoming in 1981. The remaining 18 individuals from this population were captured and put into a captive breeding facility in 1987.

Present Status:
From 1987 until 1991 the black-footed ferret may have been extirpated in the wild. In the fall of 1991, 49 captive animals were reintroduced into the wild in Wyoming. The reintroduced animals were designated an "experimental" population. Unconfirmed sightings from other areas continue to be reported. In North Dakota, the majority of the reports come from the southwest part of the state. There are still about 300 black-footed ferrets in captivity. North Dakota is being evaluated for reintroduction sites.

Habitat:
The black-footed ferret inhabits short grass prairies, always within close proximity to prairie dog towns.

Life History:
Black-footed ferrets can breed when 1 year old. Breeding takes place from March to May. Gestation ranges from 41 to 45 days. Typically, there are 3 to 4 young per litter. Young ferrets leave the family group around September. Juvenile males suffer high mortality, a result of their dispersing to new areas. Life expectancies for wild black-footed ferrets are probably less than 5 years Prairie dogs comprise 90 percent of the diet of black-footed ferrets. A black-footed ferret family of 4 will consume an average 763 prairie dogs per year. Black-footed ferrets utilize prairie dog burrows for shelter and raising families. Black-footed ferrets are primarily nocturnal. They are active in the winter.

Aid to identification:
Black-footed ferrets are 20" to 24" long, including a 6" tail, and weigh up to 2.5 pounds. They have a yellowish, brown body with a distinctive black mask across thc face, black on the feet and the tip of the tail. The related long-tailed weasel is about half the size of the ferret and does not have the distinctive black markings.

Reasons for decline:
The rapid decline of black-footed ferrets has been linked to the eradication of prairie dogs. Prairie dogs now occupy less than 1 percent of their historic range. Threats to black-footed ferrets also include canine distemper. Black-footed ferrets are susceptible to predation by golden eagles, great-horned owls, and coyotes. They are also susceptible to road kills and trapping.

Recommendations:
It's recommended that individuals contact the U.S. Fish and Wildlife Service before initiating activities that affect prairie dog towns. Report any suspected black-footed ferret sightings to a wildlife agency.

Comments:
Prairie dogs are essential to black-footed ferrets. Dog towns provide habitat for other rare species such as mountain plovers, burrowing owls, ferruginous hawks, prairie falcons, swift fox, and game species like antelope.

References:
Black-footed Ferret Recovery Plan by U.S. Fish and Wildlife Service, 1988. Handbook of Methods for Locating Black-footed Ferrets 1984, and Black-footed Ferret Habitat: Some Management and Reintroduction Consideratons 1985, both published by the Wyoming Game and Fish Commission and the U.S. Bureau of Land Management.


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