Current Program Update: May 04, 2010
Kofa NWR Desert Bighorn Sheep Herd Update
For immediate updates, check the “press releases” section.
[Please see archived updates for additional background]
The purpose of this joint Arizona Game and Fish Department and U.S. Fish and Wildlife Service effort is to restore the Kofa desert bighorn sheep herd to numbers that will once again support the herd’s critical and historic role as a source of animals for translocation to resurrect herds throughout the southwestern United States. Many herds were extirpated during the late 19th and early 20th centuries, causes are attributed to the unregulated market-hunting to support frontier development and diseases transferred from domestic livestock. However, through regulated hunting, concerned sportsmen, and the department’s translocation program, Arizona’s bighorn sheep herd is estimated at nearly 6,000 animals. Additionally, because of the program, two species of bighorn sheep now call Arizona home - the desert bighorn and Rocky Mountain bighorn.
Herd Survey Update:
The last annual Kofa NWR bighorn sheep herd survey was conducted in October 2009. That survey estimated the population on the refuge at 410 animals.
The 2009 survey estimate of 410 animals is a decrease of 6 percent from the 2008 estimate of 436 sheep, and 11 percent below the 2007 survey estimate of 460 sheep. The 2009 population is only 5 percent more than the historic record low of the 390 animals surveyed in 2006.
Biologists’ analysis of the past four surveys indicates no significant decline or improvement to the herd’s population. Wildlife agencies and conservationists remain concerned about the decline in bighorn sheep populations on the refuge, especially in comparison to the estimated 812 animals from the 2000 survey.
Historical averages for the herd before the significant decline in 2006, using the same current survey methods, put the herd at an average estimate of 732 animals (1992-2003 survey data).
The official joint news release of the survey results issued on Nov. 16, 2009 is available here.
The next annual survey is scheduled for October of 2010. Results will be posted in the press release section of this site.
The water conditions as of the spring of 2010 are very good. The above average rainfall, during the winter of 2009-10, has filled all waterholes. Frequent inspections of all priority waters have begun and will continue throughout the summer months. If it becomes necessary to maintain water availability at all priority locations, supplemental water will be hauled to these sites.
High Tank #3
In April 2010, the Arizona Desert Bighorn Sheep Society (ADBSS) partnered with the U.S. Fish and Wildlife Service / Kofa NWR (Refuge) and the Arizona Game and Fish Department (Department), to reseal the White Dike Tank (aka High Tank #3) due to excessive leaking. Click here to read the USFWS letter of appreciation on the success of this project.
This water is a rock tinaja and critical water source for bighorn sheep in the northeastern part of the Refuge. This tank started leaking last year and required aerial hauling of water in August to maintain a supply of drinking water to wildlife. Even after rains filled the tank this winter, almost all the water was lost due to leakage.
The repair was made possible by dozens of volunteers. The work consisted of removing and storing the water that was left in the tank, then cleaning out all the gravel and mud, and then applying a coat of sealant to the bedrock. After completion, the salvaged water was returned to the repaired tank and should last well into the summer.
Due to being located in the Kofa Wilderness, the project required following National Environmental Protection Agency (NEPA) processes for a categorical exclusion to conduct the maintenance on this critical natural bedrock pothole which has been in place since 1939 when the Refuge was established.
Click here to read the project description and planning documents.
Click here to read the USFWS/Kofa NWR letter of appreciation.
Predation Management and Monitoring:
Radio-collared bighorn sheep:
The following six deaths of radio-collared sheep were investigated since the last update of June 29, 2009. Four of the deaths are the result of mountain lion predation.
- July 1, 2009 – Ewe #8 was killed by an unknown lion in the upper parts of Burro Canyon.
- July 31, 2009 – Ewe #33 was killed by an unknown lion above White Dike Tank.
- Sept. 5, 2009 – Ewe #37 was found dead in a wash northwest of Wilkerson Seep, predation was not the cause of death, nor could a cause be determined. The body was found partly buried in the gravel of a wash. Drowning in a flooded wash is a possibility.
- Sept. 29, 2009 – Ewe #45 was found dead on the west side of McPherson Pass in the Castle Dome Mountains. She did not appear to have been killed by a predator and may have succumbed to either disease or malnutrition.
- Jan. 11, 2010 – Ewe #19 was killed by an unknown lion in the Livingston Hills.
- March 2, 2010 – Ewe #22 was killed by an unknown lion near Twin Spires Canyon.
Radio-collared mountain lions:
(For clarification, radio collar designations are as follows: K = Kofa collared, R = regionally collared; M = male, F = female, 01 = sequential number is unique based on location and gender, ie: KM01 = is Kofa male number 1, KF01 = would be Kofa female number 1)
- Sept. 1, 2009 – KM04 (Kofa, Male, #04): This adult male was lethally removed on Sept. 1, 2009 from the Eagletail Mountains, located about 90 miles northeast of Yuma. A radio-collar was placed on this lion in late February 2009, near Squaw Tank in the Kofa Mountains. From the time of collaring through August 2009 (approximately 6 months), it had killed 16 bighorn sheep, 11 within the Kofa Predation Management Area. This lion was not removed after becoming an offending lion (predation of more than one bighorn sheep in a 6-month period) due to a one-year moratorium between the Department and USFWS to suspend lethally removing “offending lions” collared on the Kofa Refuge. The moratorium was actually in effect from April 18, 2008 through July 31, 2009 due to a one-time extension and a reset of the KM04s record. The moratorium was in place to allow for the completion of the USFWS Environmental Assessment (EA). The EA is still pending. Due to the impacts KM04 was having on the sheep populations, the moratorium was not extended.
- April 4, 2010 – RF01 (Regional, Female, #01) – A female lion, estimated at 8-9 years old, weighing 70 – 75 pounds, and in relatively good condition for an older lion, was captured and fitted with a department-owned satellite collar on April 4, 2010 for monitoring. This lion was caught using a cage trap in GMU 41 near a site that was often visited by the male lion (RM01) just east of the Kofa Predation Management Area. This may be the first time in Arizona that a mountain lion has been captured using a cage trap. This is also the first female lion radio collared for this project. There was no indication that she had kittens with her. The only predations recorded at the time of this report are a mule deer fawn, bobcat and a coyote.
- April 20, 2010 - RM01 (Regional, Male, #01): This adult male was lethally removed on April 20, 2010 from the Painted Rock Hills north and west of Gila Bend in GMU 39. This lion was captured and collared in August 2008 in the Gila Bend Mountains. Monitoring shows that this animal ranged mostly to the east of the Predation Management Area. In May 2009, the satellite transmitter ceased functioning, however the receiver on the GPS collar continued to collect data. In October 2009 the animal was recaptured and fitted with a fully functioning GPS collar. Five months of data stored on the collar was retrieved allowing analysis of movements and any kill sites. In April 2009, it became an offending lion having killed two bighorn sheep inside the KPMA within three months. During the 20 months of monitoring (Aug. 2008-Mar. 2010) this lion killed a minimum of 52 mule deer and 14 bighorn sheep (2 in the management area).
The Department continues to seek opportunities to monitor and manage the effects mountain lions have on the Kofa bighorn sheep population while in its declined state, through tracking their range, movements, predation, and other aspects of the predator-prey dynamic.
The Kofa NWR Mountain Lion Management Plan and Environmental Assessment (EA) for “Limiting Mountain Lion Predation on Desert Bighorn Sheep on the Kofa National Wildlife Refuge” is awaiting final approval by the U.S. Fish and Wildlife Service and publishing in the Federal Register.
Translocations remain suspended at this time. The last translocation from the Kofa was in 2005. To learn more about translocations click here.
Results from blood samples taken from bighorn sheep captured and collared in November 2007, 2008 and 2009 have been received and are being analyzed. Interpretation of the results is difficult. Although titers to viral diseases such as PI3 and BRSV are often positive, the animals rarely, if ever, show clinical signs of disease. Eight of 34 samples, from the animals screened in 2009, tested positive for Mycoplasma, which is often an indicator of respiratory disease, but again, none of the animals showed symptoms of pneumonia.
Nothing new to report
The 2009 desert bighorn sheep ram hunting season (only rams are hunted) ran December 1-31. The season included 7 permit-tags (6 from Game Management Units on the Refuge and 1 from a GMU that includes a small portion of land in the northern part of the Refuge) that could have been filled on Kofa lands, the lowest number of tags issued for the refuge since 1981. Of these permit-tags, 6 rams were harvested from the refuge.
The 2010 season for bighorn sheep hunting in the Game Management Units (45A, 45B and 45C) that include the Kofa NWR are scheduled for Dec. 1-31, 2010. The Department allocated only 5 hunt permit-tags for the refuge, a decrease of 1 permit from the 2009 season. The limited hunt permit-tags were available through a lottery application process. The distribution of the hunt permit-tags are as follows: 1 tag in Unit 45A (same as 2009), 1 in Unit 45B (was 2 in 2009), and three (3) in Unit 45C (same as 2009).
A portion of Unit 44B South includes some of the Kofa NWR range in its boundaries and could include a sheep harvest from the Kofa. Only one (1) tag was allocated to Unit 44BS, bringing the maximum possible harvest from the Kofa NWR herd to 6 rams. This allocated harvest would account for only 1.5 percent of the 2009 estimated herd population. Note: With proper ram to ewe rations, limited male harvests have no effects on the breeding population.
Mandatory harvest reporting and physical check-in is required for all bighorn sheep hunters.
Additionally, there is one (1) Special Big Game Tag (Commissioner’s tag) allocated for bighorn sheep that could be used in the southwest region of the state that does include the Kofa NWR units. This special tag is valid all year long. However, historically, this tag has only occasionally been used for hunting on the Kofa NWR.
Research and Monitoring
Seventeen new or refurbished radio-collars were placed on bighorn sheep in November 2009. Eight of these were put on new animals and 9 replaced non-functioning collars on previously collared animals.
There are currently 38 working collars on bighorn sheep on the Refuge.
Twenty-six are satellite GPS collars that transmit location data daily, and 12 are VHF-only collars. The VHF collars generate a beeping radio signal. To find the location of an animal with a VHF collar, it requires a person to be in the field to track that beeping frequency to determine location and movements.
AGFD personnel and a NMSU graduate student monitor these radio-collared sheep closely. In keeping with the National Wildlife Refuge System Improvement Act of 1997, data and information is shared between these two collaring programs.
Wilderness Watch has filed an appeal with the Ninth Circuit Court of Appeals in San Francisco regarding redevelopment of two existing water catchments. The appeal was heard by the court in December 2009. A decision is yet to be announced. For information, visit the U.S. Court of Appeals for the Ninth Circuit website at, www.ca9.uscourts.gov. The case is Wilderness Watch v. USFWS, No. 08-17406.
Case history: In Sept. 5, 2008, U.S. District Court Judge Mary H. Murguia, ruled that the U.S. Fish and Wildlife Service (FWS) use of motorized equipment for the redevelopment of those tanks did not violate the Wilderness Act and the agency complied with the National Environmental Policy Act (NEPA).