Bio-Notes
Bighorn Sheep Study
The cooperative bighorn sheep mortality study with Oregon Department of Fish and Wildlife, the U. S. Fish and Wildlife Service, and the Foundation for North American Wild Sheep has continued since our last report. We had two mortalities since May both due to mountain lions. One radio collared ewe and her lamb were killed near the top of Hart Canyon in April and the second radio collared ewe was killed on the south end of Hart Mountain above Hart Lake in September. This brings the total mortality of radio collared bighorn to 10 since the study began in January 2004. Of these, 5 are confirmed cougar kills. The Oregon Department of Fish and Wildlife is working on a draft cougar management plan which contains recommendations for managing cougars in bighorn sheep habitat. In order to maintain our sample size of radio collared bighorn, we will be capturing 7 sheep in December to put radio collars on them that have been retrieved from mortalities. This redistribution of radio collars will enable us to continue monitoring bighorn on Hart Mountain for mortality as well as assess movement and habitat use patterns throughout the year.
What is Radio Telemetry?
Radio telemetry for wildlife was developed in the 1950s. This technology, which uses bands and frequencies much like your AM and FM radio stations, enables biologists and managers to closely monitor mortality, movements, and habitat selection of many wildlife species. During wildlife captures (on Hart Mountain these currently include bighorn sheep, pronghorn fawns, and sage grouse) radios are either affixed to the animal using collars or glue. The radios are programmed with two modes, alive and mortality. If an animal dies the collar automatically switches to mortality mode and the signal from that collar doubles in speed. Signals are obtained using a receiver and an antenna. The information collected can help us to plan management activities such as prescribed fires, provide information when discussing hunting tag limits with the Oregon Department of Fish and Wildlife, and provide baseline habitat use information.
Bighorn Sheep Transplant
During the sheep capture in December, Oregon Department of Fish and Wildlife (ODFW) also captured and transported 25 bighorn sheep to Red Wall, Idaho. This augmentation project is intended to provide "seed sheep" in an area previously uninhabited by sheep to encourage resident sheep to colonize this very suitable habitat. Twenty-one ewes and 4 rams were captured by the Hawkins and Powers Company using a helicopter and net guns. The captured sheep were transported via helicopter to Refuge headquarters where we drew blood, used a portable sonogram unit on the ewes to detect pregnancy, collected fecal samples, and fitted each sheep with a radio collar. The sheep were then placed in special boxes mounted on trucks and transported to their new home at Red Wall, Idaho.
Bighorn Sheep Population Survey
Each summer, we survey bighorn sheep on Hart Mountain using a helicopter with two observers. We fly sheep habitat from the north boundary to the south boundary on the west side of the Refuge. This information allows us to work with Oregon Department of Fish and Wildlife (ODFW) in setting harvest limits and bighorn sheep transplant operations. These data are also important to hunters and casual visitors alike to the Refuge. We flew the bighorn sheep survey on 18 July 2005 using a Bell B3 helicopter piloted by Jeff Lindscott of JLA Aviation, Portland, OR. We started at 06:45 and ended the survey at 11:20. Weather conditions were clear with no wind at the beginning and 64 degrees F. At about 10:00 the wind picked up and classifying sheep became more difficult. There were two observers in the helicopter, Craig Foster, Oregon Department of Fish and Wildlife and Rachelle Huddleston-Lorton, Hart Mountain Refuge biologist spotting sheep with the pilot also helping to spot groups of sheep. We recorded data (numbers of sheep, classification, and the number of radio collars seen) on standardized data sheets (HMNAR files 6004.2). We observed 286 bighorn sheep from the north Refuge boundary on Poker Jim Ridge to Riffle Canyon on the south end. There were 99 rams, 124 ewes, and 63 lambs. We saw 28 sheep with radio collars; thus we calculated a 77.8% observability rate. Based on this observability, we estimate the bighorn population on Hart Mountain to be 350.
Pronghorn Fawn Mortality Monitoring
Once again, in May we captured and fitted 21 pronghorn fawns with ear-tag mounted radios to monitor mortality rates and causes during the first 6 weeks of their lives. Eleven (52.3%) fawns died during the project period: 4 (36.4%) were killed by bobcats, 3 (27.3%) by coyotes and 4 (36.4%) of unknown causes. There were more fawns killed by bobcats this year than any other year of this project. All bobcat mortalities occurred on Blizzard Ridge. Because of the high rainfall in May the grass grew very tall all over the Refuge. This provided ample cover for bobcats to stalk and kill pronghorn fawns. As usual, we could not have accomplished this project without the many volunteers who assisted us in this endeavor. Special thanks to Dr. Dean Bauman, veterinarian extraordinaire who assisted us with blood draws on the fawns and to Lori Chappel who did the "blood run" to town every day, delivering the fawn blood to the Lake District Hospital where it is analyzed. We would also like to thank the Order of the Antelope Foundation for continued support to this valuable project.
Pronghorn Hoof and Mouth Disease - update
In May 2004, 11 pronghorn fawns were captured and transported to Colorado State University where they participated in a hoof and mouth disease study. An April 2005 project update reported that all 11 fawns were alive and doing well.
Pronghorn Population Survey
Each year we fly pronghorn surveys to count and classify pronghorn on Hart Mountain NAR. Annual surveys allow refuge managers and biologists to track population trends and to coordinate hunting tag allocations with the Oregon Department of Fish and Wildlife. Observers included Rachelle Huddleston-Lorton, (USFWS) Refuge Biologist, Craig Foster (Oregon Department of Fish and Wildlife), District Biologist, and Jeff Lindscott (JLA AVIATION), owner/pilot. We started the survey at 06:00 and completed it at 11:30. Weather conditions were ideal for flying, no wind, 68 degrees F, and clear. We flew the Refuge west to east in mile-wide transects starting on North Mountain, continuing across South Mountain, and then on to the desert section. The intermediate hills, north-east flats, and Poker Jim Ridge were the final segments of the survey. We counted pronghorn groups and then classified them according to age (yearling male, fawn) and gender. During 5.5 hours of surveying, we observed and classified 2372 pronghorn. We observed more pronghorn in the southern sections of the Refuge than in the northern areas and ratios of males to females and fawns to females were higher than in the previous five years (61 bucks per 100 does and 59 fawns per100 does).
Sage Grouse Lek Survey
Lek surveys are conducted each spring to determine the maximum number of males attending the leks. Lek is a Swedish word meaning "to play" and "arena". Sage grouse leks are exactly that, arenas where males come to strut and boom, trying to attract females. The females come to the leks to watch and then choose their mate. Once again this year we had several die-hard volunteers who arrived in March to help out with the surveys. Morrie Chappel, President of the Friends of Hart Mountain NAR and George Reynolds, Past President of the Friends of Hart Mountain NAR both arrived at the onset of lek season, March 15, and stayed through the entire 6 week survey period, surveying leks during inclement weather and below freezing temperatures. This year peak male attendance at the leks was 1898 up from 1671 last year! That's an increase of more than 11%! We have had several mild winters and over winter survival of sage grouse has been high (we know this from radio-collared hens from last spring). If you would like a chance to participate in these surveys next spring, please contact the Hart Mountain biologist.
Sage Grouse West Nile Virus Study
Teaming up with the National Wildlife Health Laboratory, United States Geological Survey (USGS), and the Oregon Department of Fish and Wildlife (ODFW), we are studying West Nile Virus in sage grouse on Hart Mountain. In April, we captured and radio-collared 8 male grouse and 5 female grouse. We had hoped to radio an additional 12 grouse during the spring or summer but were unsuccessful in our capture attempts. We monitored the 13 radioed grouse at least three times a week during the mosquito season (July, August, and September) for mortalities. We had no mortalities during the monitoring period which is good news with respect to West Nile Virus on Hart Mountain. The USGS has funding for additional West Nile virus research next year and would like to continue this project on Hart Mountain next summer.
Pygmy Rabbits
We continue to survey for pygmy rabbits in the Wyoming big sagebrush project areas on the northeast portion of the Refuge. We have captured and radio collared 21 rabbits and are monitoring those radios at least 2 times each week to assess mortality and movements. These radios are being used to monitor the effects of habitat treatments on pygmy rabbits. Since we started capturing pygmy rabbits in August 4 rabbits have died and 1 is missing in action (no signal detected since collaring). The most common cause of death is predation by weasels. The weasels travel underground through burrow systems used by pygmy rabbits and often we have to dig out a burrow to retrieve the radio and what is left of the rabbit. We continue to capture rabbits and place radios retrieved from mortalities on them to maintain our sample size.
Winter Raptor Survey
The Oregon statewide winter raptor surveys are a joint venture between Jeff Fleischer and the East Cascades Birds Conservancy. Beginning in November we will once again participate in this project. Survey routes include the Lakeview area and Plush-Adel and the Refuge. We have several volunteers who have expressed an interest in conducting these auto route surveys this year. We will survey each route during November - March to assess wintering raptor populations in this part of Oregon.
Christmas Bird Count 2005
Each year Refuge staff participates in the National Audubon Society's Christmas Bird Counts (CBC) on Hart Mountain and in the Adel area. We will conduct the Hart Mountain CBC on December 17, 2005 and the Adel Circle CBC on December 18, 2005. Please contact me if you would like to join us on this count. Christmas Bird Counts are conducted throughout the world each year and provide important information about wintering songbirds, raptors, and owls.
Outreach and Education
The Plush School had a field trip to Hart Mountain in October 2005. These students (kindergarten through 3rd grade) came to Refuge headquarters for a short presentation about Refuge programs and then we went into the field looking for pygmy rabbits. Unfortunately, we did not catch any rabbits that morning but they did help me find a rabbit in a burrow that had been killed by a weasel. We dug up the rabbit and looked at the evidence of weasel predation; tiny bite marks on the collar and location of the rabbit were the main indicators that a weasel had killed the rabbit. Also during the summer, we had a group of summer students from the Oregon Museum of Science and Information (OMSI) in Portland, OR. These students came from all over the world (one student was from South Africa) and I spent a day in the field with them discussing Refuge programs and looking for bighorn sheep. The U.S. Fish and Wildlife Service and Oregon Department of Fish and Wildlife (ODFW) offered a bighorn sheep viewing trip for auction at the annual Foundation for North American Wild Sheep (FNAWS) banquet. Four people spent a weekend in October 2005 on Hart Mountain with ODFW district biologist Craig Foster observing bighorn sheep. This is the second year that we have participated in this fund raiser for FNAWS. The Foundation for North American Wild Sheep is a non-profit organization dedicated to the conservation of wild sheep. They have helped to fund the current bighorn project on Hart Mountain and have been instrumental in re-establishing bighorn sheep populations all over the west.
Wyoming Big Sagebrush Project
Data collection continued this summer to assess pre-treatment vegetation conditions in the Wyoming big sagebrush project area. Information on plant species richness, density, and canopy cover was collected. We applied Spike (Tebuthiuron) to about 440 acres of sagebrush in October at a rate of 0.75 lbs. active ingredient per acre. Spike is best applied to sagebrush in the fall before the winter precipitation arrives. It is a pellet form of herbicide that disintegrates during the winter and begins to kill sagebrush. We will be revisiting the monitoring plots and transects next spring/summer to assess cheat grass invasion, decreases in the sagebrush canopy cover, and emergence of native grasses and forbs. We will also be mowing about 440 acres of sagebrush this fall and repeat the plot and transect work to assess the same issues: cheat grass, sagebrush canopy cover, and native grasses and forbs. We had initially planned to burn 640 acres of sagebrush as part of this project but decided that the risk of cheat grass invasion was too high. The pygmy rabbit radio collaring study is a component of this project, intended to provide information about the effects of habitat treatments on pygmy rabbit survival and habitat use.
Effects of Fire and Fire Surrogate Treatments on Sage Grouse
We intended to monitor the effects of habitat treatments on sage grouse and radio collared several from the Wyoming big sagebrush project area with that in mind. However, the grouse have not been cooperative and did not remain within or adjacent to the project area. We monitored these radios throughout the summer months however as part of the West Nile Virus (WNV) study with U.S. Geological Society (USGS) so not all was in vain. These radios will be monitored next year for WNV as well.
Fire Monitoring
Working with a volunteer we were able to complete vegetation transects in the 1994 Blizzard North burn area during the summer of 2005. I have not had a chance to analyze the data yet but will hopefully have that for you in the Spring 2006 newsletter.
Weed Mapping
We received grant money to initiate mapping of invasive species on Hart Mountain this year; however, the money did not arrive in time for us to begin during this growing season. We were able to purchase equipment this year including two Trimble GPS units, a plotter (large format printer for printing maps), and a laptop to run GIS software. We also partnered with the Warner Basin Weed Group and were able to secure funds to buy herbicide for the local ranchers to continue the fight against invasive species in the Warner Valley.
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Contact
Friends of Hart Mountain38782 Hart Mountain Rd
Plush, OR
97637
541-947-2731
friendsofhartmountain@yahoo.com