Ferret with the black feet....

Ferret with the black feet, soon to be chopped meat! (without our help)

Black-footed Ferret

http://azgfd.net/artman/uploads/1/kits_in_burrow2-2_1.jpg

By Aidan Kelly

Description and Ecology of Organism

The black-footed ferret (Mustela nigripes) is a mustelid who's appearance consists of a yellowy white core, black feet and tail tip, and a “black mask” around the eyes. They are two feet long, give or take, and 1.5 to 2.5 pounds. Coincidentally, that is about the size of their food source, the black-tailed prairie dog. The ferrets prey on a variety of prairie dog species, which inherently dictates their habitat. Black-footed ferrets also transform prairie dog burrows their home because they don’t dig their own. Black-footed ferrets are nocturnal and extreme specialists when it comes to meals and shelter.  Mustelids generally have short life spans of four to five years and a high juvenile mortality rate. The early mortality rate, averaging fifty perfect or more, has a huge impact on their population growth.

http://www.fws.gov/endangered/news/images/bulletin_spring2009-ferret1.jpg

Geographic and Population Changes

The black-footed ferret is the only ferret species in it’s genus that originates from the Americas. They are estimated to have arrived in North America from Siberia one to two million years ago. Historically, like present day trends, the ferrets inhabited the same territories that prairie dogs did. These territories include mountains and grasslands from Canada through the US midwest to Mexico. Female territorial range is around thirteen hectares while male territory is 36 hectares (Livieri and Anderson 2012). Ferret populations starting declining when prairie dog populations did due to habitat destruction, poisoning, and disease. Currently, all known ferret populations are the result of human reintroduction. The last wild population was observed in South Dakota 40 years ago (Clark 1989). When the last ferret of that population died, the species was thought of as extinct. This was proven untrue when a small population was discovered in Wyoming. Before disease outbreaks had a chance to hurt the population, the wild ferrets were captured and used in a breeding program to reestablish population numbers. The most recent population count (2012) from all the released ferrets yields 362 breeding adults, according to the recovery plan. 

http://outdoornebraska.ne.gov/wildlife/images/fermap.jpg

Listing Date and Type of Listing

Black-footed ferrets were recognized as endangered in 1967 by the United States and were officially enlisted as endangered when the Endangered Species Act was created in 1973. The species was just listed as “endangered” though critically endangered may have been appropriate granted that there was only eighteen ferrets alive in the world to biologist’s knowledge. 

Cause of Listing and Continuous Threats

According to the Fish and Wildlife Service, the three main threats to the black-footed ferrets is their native homelands being converted to croplands, the poisoning of prairie dogs, and disease. As we know, black-footed ferrets habitats overlap with prairie dogs so when there was a 90 percent decrease in suitable habitat for prairie dogs, the ferrets were affected as well. The reduction of suitable habitat was a consequence of land conversion for crops and subsequent poisoning that occurred. In 2006, 45 million hectares of prairies that were inhabited by ferrets had been converted to croplands (Ernest et al. 2006). What’s more, 1.3 million hectares of black-footed ferret habitat has also become urbanized. Poisoning of wildlife is evidently a by-product of these sources of habitat destruction. Poisoning is a dramatic threat to ferrets because they can receive it directly, or second handedly through ingesting poisoned prairie dogs. Prairie dog poisoning programs were used from 1916 to 1920 because they competed with livestock for edible forage. Lastly, the  Sylvatic plague has brutally lowered ferret populations. This bacterial disease is transmitted through flea bites or pneumatically. Prairie dogs can contract the plague as well; thus, increasing the chances of ferrets catching it. Recent studies have estimated that 75 percent of the ferret population at a previous release site died from the disease (Griebel 2008). It should be noted that whatever threats are posed to prairie dogs directly or indirectly affected the ferret. At this point, black-footed ferret recovery is a waiting game because it depends on the prairie dog population comeback. Climate change, inadequacy of existing regulatory mechanisms, and recreational shooting of prairie dogs are all underlying factors in the black-footed ferret decline.  

http://ecos.fws.gov/docs/recovery_plan/20131108%20BFF

%202nd%20Rev.%20Final%20Recovery%20Plan.pdf

One variety of poisoned used
http://www.newtree.com.ph/products/490-1.jpg

Description of Recovery Plan

The purpose of the plan is to downlist the black-footed ferret to “threatened” rather than “endangered” and ultimately delisted completely. This is projected to be achieved by 2023 and 2043, respectively. The criteria for downlisting the species is as follows: 1) manage a captive breeding program of 105 males and 175 females dispersed among, at minimum, three facilities, 2) establish free ranging ferret population with at least 1,500 breeding adults, in 10 or more populations, in at least half of the states containing their historical range, 3) maintain aforementioned criteria for 3 years prior to downlisting species, and 4) maintain a 100,000 hectare habitat for prairie dogs by conservation and managing the sylvatic plague. 

http://ecos.fws.gov/docs/recovery_plan/20131108%20BFF

%202nd%20Rev.%20Final%20Recovery%20Plan.pdf

Citations (all from the BFF Recovery Plan):

 Livieri, T.M. and E.M. Anderson. 2012. Black-footed ferret home ranges in Conata Basin, South Dakota. Western North American Naturalist 72:196-205.

 Clark, T.W. 1989. Conservation biology of the black-footed ferret Mustela nigripes. Wildlife Preservation Trust Special Scientific Report No. 3. pp 175 

 Ernst, A.E., A.L. Clark, and D.R. Gober. 2006. A habitat-based technique to allocate black- footed ferret recovery among jurisdictional entities. In Recovery of the Black-footed Ferret: Progress and Continuing Challenges. Edited by J.E. Roelle, B.J. Miller, J.L. Godbey, and D.E. Biggins. U.S. Geological Survey. Pp. 89–95.

 Bell, W. 1921. Death to the rodents. U.S. Department of Agriculture. 1920 Yearbook. Pp. 421–438.

 Griebel, R.G. 2008a. U.S. Forest Service. E-mail update on plague at Conata Basin. Personal Communication with BFFRIT. September 3, 2008.

Supporting sources:

http://www.defenders.org/black-footed-ferret/basic-facts

http://ecos.fws.gov/docs/recovery_plan/20131108%20BFF%202nd%20Rev.%20Final%20Recovery%20Plan.pdf