Black-footed ferrets (Mustela nigripes) apparently were extirpated from all native habitats by 1987, and their repatriation requires a combination of captive breeding, reintroductions, and translocations among sites. Improvements in survival rates of released ferrets have resulted from experience in quasi-natural environments during their rearing. Reestablishment of a self-sustaining wild population by 1999 provided the 1st opportunity to initiate new populations by translocating wild-born individuals. Using radiotelemetry, we compared behaviors and survival of 18 translocated wild-born ferrets and 18 pen-experienced captive-born ferrets after their release into a prairie dog colony not occupied previously by ferrets. Translocated wild-born ferrets moved significantly less and had significantly higher short-term survival rates than their captive-born counterparts. Using mark–recapture methods, we also assessed potential impacts to the established donor population of removing 37% of its estimated annual production of kits. Annual survival rates for 30 ferret kits remaining at the donor subcomplex were higher than rates for 54 ferret kits at the control subcomplex (unmanipulated) for males (+82%) and females (+32%). Minimum survival of translocated kits did not differ significantly from survival of those at the control subcomplex. Direct translocation of young, wild-born ferrets from site to site appears to be an efficient method to establish new populations.
Evaluation of a black-footed ferret resource utilization function model
As snow blankets the ponderosa-pine slopes and temperatures stay below freezing for weeks on end, it seems unlikely that any warm-blooded creature would choose the Black Hills of South Dakota as a winter home. However, just inside Jewel Cave, over one thousand bats quietly hang from the walls and ceiling, their hearts only beating every few seconds and their breathing scarcely discernible. Deep in hibernation, these bats take advantage of cool temperatures within the cave to induce their winter sleep. Clustered together in tight groups, male and female bats endure the winter, waiting for warm spring temperatures and the re-emergence of their insect prey.
In early spring, the Jewel Cave colony breaks up and most of the bats leave the cave to find warmer summer roosts. While males set off to roost alone or in small groups, females gather together to form maternity colonies where they take advantage of each others company and communally raise their young. So begins the breeding season of a bat community in the Black Hills...
FORT researchers meet the challenges of re-establishing the endangered black-footed ferret
More than twenty years have passed since the discovery, in 1981, of the last known wild population of black-footed ferrets near the small town of Meeteetse, Wyoming. This secretive, nocturnal member of the weasel family was thought to be extinct, or nearly so. The black-footed ferret was known to be very dependent on large colonies of prairie dogs, but little else was known about these rarely seen animals.
What started with excitement over their discovery, however, soon degraded into a frantic effort to save the last of a dying population. Distemper and plague, both introduced diseases, were discovered on the prairie dog colony that supported the ferret population. Between 1981 and 1987 the Meeteetse ferret population dropped from an active community consisting of many family groups to only 14 individuals captured to save the species. Those 14 animals became the future of the black-footed ferret recovery program...
Organochlorine and mercury residues in Swainson's and ferruginous hawk eggs collected in North and South Dakota, 1974-79
Stendell, R.C., D.S. Gilmer, N.A. Coon, and D.M. Swineford