Wyoming wolf update
by U.S. Fish & Wildlife Service
November 25, 2008
WYOMING WOLF WEEKLY- Nov. 10, through Nov. 21, 2008
Routine aerial telemetry flights are being flown throughout Wyoming to identify wolf packs, determine pack composition, and estimate the total number of wolves. Once snow is on the ground, we normally increase the frequencies of flights to confirm new packs as well as determine if some suspected packs do not actually exist. We predict that the total number of wolves in Wyoming in 2008 will slightly decrease compared to the number of wolves in 2007. Preliminary counts in Yellowstone National Park indicate fewer wolves in 2008, while the number of wolves in Wyoming (outside YNP) in 2008 will be very similar compared 2007 (approx. 180-190 wolves). The USFWS will provide final minimal wolf population estimates in the 2008 Annual Report which will be completed by the end of February 2009.
Table 1. Number of wolves in Wyoming (outside YNP) and Yellowstone National Park, from 2003 through 2007.
Wyoming (outside YNP):
2003 - 88
2004 - 101
2005 - 134
2006 - 175
2007 - 188
2003 - 174
2004 - 171
2005 - 118
2006 - 136
2007 - 171
2003 - 252
2004 - 272
2005 - 252
2006 - 311
2007 - 359
Yellowstone Park began its annual winter study on November 15. Research objectives include:
1) documenting kill rates of wolves;
2) determining prey selection; and 3) estimating annual wolf population numbers. Park biologists suspect that the number of wolves in YNP in 2008 has decreased due to adult wolf mortality from conflicts between packs, increased pup mortality, and mange. Mange has been documented in >8 wolves from four different packs (Oxbow Creek, Mollies, Leopold, and one unnamed group of 4 wolves).
University of Wyoming students Abigail Nelson and Arthur Middleton presented updates on their graduate research in the Absaroka/Sunlight Basin areas. Both projects are cooperative efforts between the University of Wyoming, Wyoming Game and Fish Department, the U.S. Fish and Wildlife Service. Abby’s project is titled: Wolf habitat selection and predation patterns in the Absaroka Mountains of Wyoming: Identifying the landscape drivers of wolf-livestock conflicts. Arthur gave an update on his research and discussed his research objectives:
1) Determine the status of migratory and non-migratory elk in the Clark’s Fork Herd Unit;
2) Determine the timing of migrations and routes used by migratory elk;
3) Increase the understanding of elk use of private lands;
4) Determine adult female survival rates; and
5) Evaluate the influence of wolves on elk habitat use and movements.
Scott Becker, recently graduated from the University of Wyoming, presented the results of his masters research. His abstract states: "Since the establishment of a self-sustaining population of Shiras moose (Alces alces shiri) in the Jackson Valley around 1912, moose populations have fluctuated over time. These fluctuations were thought to be driven primarily by density dependent factors during the 1950s and 1960s. More recently, however, population trend data has suggested that the north Jackson moose herd has been in decline although wildlife managers have attempted to halt the downward trend by reducing harvest. Also during this period, large predators have increased in number and expanded their range which has led to questions regarding the relative influence of potential limiting factors. The purpose of this study was to investigate the relative influence of habitat and predation on the north Jackson moose herd using a combination of physiological health indices and population demographics.
We used the animal indicator concept to infer habitat quality from physiological parameters and estimated population vital rates from 2005-2007. Evidence suggested that the study population appeared to be declining. The preponderance of evidence indicated that habitat quality and its effect on the physical condition and reproductive output of adult females was the most likely limiting factor. We suggest that the influence of bear and wolf predation, although present, had minimal impact at the population level.
While we were not able to fully explore the specific elements of habitat quality that may be affecting this population, a better understanding of the relative influence of winter and summer habitat and the availability of thermal refugia will be vital in determining relative what management actions, if any, will be effective in altering the dynamics of this herd unit."