Arizona Game and FIsh Department - Managing Today for Wildlife Tomorrow: Arizona Game and Fish Department

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Past Program Update

NoteProgram updates will be provided at least monthly.  Interim updates may be provided when events deemed especially significant occur.   

October 31, 2007 Update

Survey Update:

  • The first annual survey of the Kofa NWR bighorn sheep herd since 1992 started on October 30.  Absent unusual weather or other unexpected circumstances, the survey will be completed by November 5.  As usual, the data collected will require several weeks of analysis before we will have this year’s population estimate.  That estimate will be announced in a future update. 
  • Annual surveys were conducted on the refuge until funding constraints forced us to begin triennial surveys, the first of which was conducted in 1994.
  • The Kofa NWR survey concludes the 2007 Region IV desert bighorn sheep survey window which started October 15.  Triennial surveys of selected bighorn populations were conducted in Game Management Units (GMU) 40A, 40B 42, 43B, 44A, 44B

Water Management:

  • The two wildlife waters -- Yaqui Tank (11,000 gallons) and McPherson Tank (9,300 gallons)-- redeveloped earlier this year both have shown bighorn use.   Bighorn sheep began using the drinker at the redeveloped Yaqui Tank within a week of its installation on June 3.  The McPherson Tank redevelopment was completed on Jun 16. 
  • Both tanks were partially filled following their installation and summer rains later filled them both to their full capacities.  Our experience with these buried tank systems indicates that it will be years before these tanks need water replenishment, even with the high wildlife use rates that we see during the most extreme drought conditions.  This significantly reduces the disruption of wildlife and the impact on wilderness that accompanies the often frequent replenishment activities required to sustain less reliable waters.
  • The summer rains, while not great, were good to us this year, with the Kofa Mountains receiving as much as 6” and the Castle Domes around 4”.  This has greened up much of the refuge’s forage plants and has replenished many natural and manmade/modified waters throughout the refuge.  This has had the affect of spreading bighorn water use across many different water sources, thus reducing the use of those critical waters (like Yaqui and McPherson) that are a priority for us when the ongoing drought once again dries out the many less reliable water sources.
  • U.S. Fish and Wildlife Service (USFWS) has negotiated a contract to conduct an Environmental Assessment for future water development on the Kofa NWR.

Predation Management:

  • A large adult male mountain lion was capture in the Burro Canyon area in the western Kofa Mountains on October 21.   He was fitted with a GPS radio collar and released.  Over the next two days we were able to confirm the collar is working and providing data.  At this point there is nothing significant to report.  Future updates will provide information about confirmed predation and other items of interest.
  • This is the third lion to be collared on the refuge this year.  The first lion – a young adult male (KM01) -- was killed while off the refuge by Department staff on June 3 after having become an “offending lion” under the Department’s Kofa Mountain Predation Management Plan.  Under that plan, an offending lion is one that has killed at least two sheep within a six-month period.  When taken at Dripping Springs, this lion was sitting on three fresh kills:  two bighorn and a mule deer.  By backtracking on the data in this lion’s GPS collar, this lion’s confirmed kills were:  five bighorn sheep, two mule deer, 2 unidentified large ungulates (either bighorn or mule deer), and one coyote.   Extensive mountain lion research indicates an adult lion kills an average one large ungulate a week (pregnant females and females with cubs kill more frequently), so there are no doubt kills that we have not found.
  • A second lion – another young adult male (KM02) – was captured, collared and released on June 4.  After only 53 days, the collar malfunctioned and dropped off on July 26, some 10 months early.  At that time, the lion was operating in an area southeast of the refuge.   Again using the data in the GPS collar, researchers confirmed the following kills for this animal:  four mule deer, 1 bighorn sheep, 2 coyotes, and a badger.  Two bighorn lambs were found in association with the movement track of this lion, but the condition of their remains precluded confirmation of the cause of death.  The one confirmed bighorn kill occurred outside the geographic area covered by the Kofa Mountains Predation Management Plan and was not counted toward offending lion status for this lion.
  • When compared with management plans for other at-risk or stressed southwestern bighorn populations (The Sierra Nevada herd, the Peninsular Bighorn herd, and herds in New Mexico) The offending lion criteria established for predation management in the Kofa Mountains Complex is the most conservative.  Mountain lion research seems to indicate that some lions will specialize in preying on bighorn sheep while others will rarely take a bighorn.  Lions that do not focus their predation on bighorn sheep by killing at least two in a six-month period will not be removed.
  • There has been no reported USFWS action on further development of an Environmental Assessment for removal of offending lions from the refuge portion of the Kofa Mountains Complex.  


  • No transplants are planned for the Kofa NWR herd.  The last transplants from this herd occurred in 2005 when 30 Kofa bighorn were collected and sent to the San Andres NWR in New Mexico to sustain that herd.
  • Pending the outcome of this year’s surveys, transplants are planned in November to move sheep from bighorn herds elsewhere in Region IV.  These herds are outside the Kofa Mountains Complex

Disease Monitoring:

  • Disease monitoring is normally conducted in conjunction with samples taken during collaring or transplant operations.  Additional information is also provided by hunter reports during the hunting season.  There has been no sampling in this population since those taken during the 2005 transplant.  No unusual disease indicators were noted at that time.
  • There is also a mandatory check-out of all animals taken during the annual bighorn sheep season.  No disease indicators were noted at the check-outs during the 2006 season. 
  • There will be a research collaring effort on the Kofa NWR starting this November.  Samples will be collected from those animals captured during that effort and tested for disease and parasites.

Recreational Impact on Bighorn Habitat:

  • The Kofa NWR staff has developed a plan for monitoring recreational impacts on selected sites as we re-enter the period of maximum recreational use this fall.  The main focus will be on potential impact on critical bighorn lambing grounds, which are generally in the higher and less accessible areas of the Kofa and Castle Dome Mountains.


  • The bighorn sheep season for the Kofa NWR occurs during the month of December 2007 and only rams are hunted.  For the 2007 hunt, 12 tags are available for the Kofa NWR.  This is the lowest number of tags issued for the refuge since 1981.

  • Paradoxically, despite the overall population decline, the number of mature class III and IV rams remains high and far exceeds the number required for reproductive needs of the herd.  Biologically, the ewe component of the herd plays the most critical role in bighorn reproduction and harvest of the targeted number of rams will have no impact on the herd’s reproductive potential. 
  • The Department has long used the most conservative end of its hunting guidelines methodology to determine hunt recommendations for the Kofa NWR. 

  • As in past years, there is a statewide tag that is auctioned to generate funding for bighorn sheep management throughout the state.  The tag may be used to hunt in any legal game management unit.  If used on the Kofa, this would constitute a 13th tag.


  • A joint U.S. Fish and Wildlife Service/Arizona Game and Fish Department bighorn research project will begin on November 1.   Under the auspices of the New Mexico Cooperative (U.S.) Fish and Wildlife Research Unit at New Mexico State University, up to 45 Kofa NWR bighorn sheep will be collared with a combination of both GPS satellite and VHF radio collars to study nutrition and predation.  

Litigation on Kofa NWR Wildlife Waters:

  • In June, Montana-based Wilderness Watch filed suit against the U.S. Fish and Wildlife Service over the redevelopment of the Yaqui and McPherson Tank wildlife waters on Kofa NWR.  They were joined in the suit by the Arizona Wilderness Coalition, the Grand Canyon Chapter of the Sierra Club, the Western Watersheds Project, and the Grand Canyon Wildlands Council.  Essentially, the suit asks that:
  • The categorical exclusion and minimum tools analysis process used by USFWS to make its decision to redevelop these waters be declared inappropriate,

  • An Environmental Assessment or Environmental Impact Statement be required, and

  • The redeveloped waters be rendered unusable.

  • In July, the Arizona Game and Fish Commission voted unanimously to request the court’s permission to intervene in the lawsuit and become a co-defendant with the USFWS in the suit.  The court has not yet acted upon the Commission’s request, but has permitted the Department to participate in the lawsuit and file briefs as if it was a party. 

  • Other organizations that have entered papers on the issue in support of active water management on the Kofa NWR include Safari Club International, the U.S. Sportsmen’s Alliance, the Arizona Desert Bighorn Sheep Society, and the Yuma Valley Rod and Gun Club.
  • Due to the technical and legal nature of this litigation, detailed information requests will need to be forwarded to the USFWS.



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