Northern Yellowstone Cooperative Wildlife Working Group 2012 Annual Report (October 1, 2012-September 30, 2012) Member Agencies Montana Fish, Wildlife & Parks National Park Service, Yellowstone National Park U.S. Forest Service, Gallatin National Forest U.S. Geological Survey, Northern Rocky Mountain Science Center Prepared by: Paul Cross, U.S. Geological Survey February 2013 This report was prepared to document achievements, record new goals, and provide a current source of biological information on the status of northern Yellowstone wildlife and wildlife-related studies to agency decision makers and the public. It has not been formally peer reviewed or disseminated by the agencies. It does not represent and should not be construed to represent any agency determination or policy.
Northern Yellowstone Cooperative Wildlife Working Group 2012 Annual Report (October 1, 2011-September 30, 2012) Introduction On February 12, 1974, representatives from the Gallatin National Forest, Montana Fish and Game Commission, and Yellowstone National Park formed the Northern Yellowstone Elk Working Group to focus on the management of the northern Yellowstone elk population. Over time, the focus of this committee evolved by necessity and consensus from a single species interest group into a multiple species and wildlife habitat oriented working group. Thus, a revised Memorandum of Understanding with expanded goals and objectives, individual agency commitments, organizational procedures, and a name change to the Northern Yellowstone Cooperative Wildlife Working Group was completed in 1994. The National Biological Survey was added to the group as a technical support member. Subsequently, the National Biological Survey was transferred to the U.S. Geological Survey and renamed the Biological Resources Division. The Memorandum of Understanding was revised again in October 2004 to reflect changes since 1994 and increase the group s effectiveness. The MOU was reauthorized by member agencies for 5 more years in October 2009. The purpose of the Working Group is to cooperatively preserve and protect the long-term integrity of the northern Yellowstone winter range by increasing scientific knowledge of its species and habitats, promoting prudent resource management activities, and encouraging an interagency approach to data collection, answering questions, and solving problems. The Working Group is composed of one designated manager and one wildlife biologist from each member agency. The Gallatin National Forest, Montana Department of Fish, Wildlife, and Parks, and Yellowstone National Park are units of natural resource management agencies with responsibility for management of wildlife and their habitats on the northern Yellowstone winter range. The Northern Rocky Mountain Science Center is a research institution of the U.S. Geological Survey with responsibility for scientific investigation of natural resources and technical support for natural resources management, primarily for the Department of the Interior. Group funds are spent primarily on annual wildlife surveys. The designated members of the Working Group during this report period were as follows: Agency Manager Wildlife Biologist National Park Service, Yellowstone National Park P. J. White Doug Smith Montana Department of Fish, Wildlife and Parks Howard Burt Karen Loveless U.S. Forest Service, Gallatin National Forest Rachel Feigley/Jodie Canfield U.S. Geological Survey Paul Cross The Working Group meets twice a year, typically in May and October. Additional meetings or subgroup meetings may be held, as necessary, to discuss issues and projects. All decisions are based on consensus and made following open discussion and debate. The Chair of the Working Group is rotated annually between member agencies. The Chair is responsible for producing an annual report that summarizes the group s activities on a federal fiscal year basis (i.e., October 1 through September 30). Additional information on the Working Group is available in the 2009 Memorandum of Understanding, which can be obtained from group members. This report summarizes the cooperative activities conducted by the Working Group during October 1, 2011, through September 30, 2012. The report is organized by species and special project sections and includes a cost summary of cooperatively funded wildlife surveys. Elk Surveys The status and distribution of northern Yellowstone elk is monitored using aircraft to conduct annual winter counts, surveys of elk migrating north of Yellowstone National Park, late-winter classification 2
surveys, and spring carcass counts. The Working Group also monitors the results of the general and late season elk hunts managed by Montana Fish, Wildlife, and Parks. Cooperative Winter Elk Counts Since 1986, the Working Group has conducted annual trend counts of northern Yellowstone elk during December/January using four Super Cub airplanes; each covering a segment of the winter range (both inside and outside the park). Ideally, the range is surveyed during one day prior in the first week of January. Due to sightability (i.e., detection) bias, these aerial counts provide a variable underestimate of the elk population size. No counts were conducted during the winters of 1996 and 1997 and counts in 1989, 1991 and 2006 were deemed poor owing to unfavorable survey conditions. The Northern Yellowstone Cooperative Wildlife Working Group conducted its annual winter survey of the Northern Yellowstone elk population on March 7, 2012. The survey, using three airplanes, was conducted by staff from the Montana Department of Fish, Wildlife, and Parks and the National Park Service. Staff counted 4,174 elk, including 1,440 elk (34%) inside Yellowstone National Park and on Deckard Flats south of Bear Creek and 2,734 elk (66%) elsewhere north of the park (Figures 1-3). Survey conditions were favorable across the region with fresh snow and good visibility. The count of 4,174 elk at the close of the 2012 winter season was ten percent lower than the 2011 winter count of 4635 and much lower than the counts of 6,070-7,109 elk during winters 2007-2010. The decrease in elk numbers likely reflects the continued effects of predation by wolves and other large carnivores such as grizzly bears, past harvests of elk during public hunts, drought effects on maternal condition and recruitment during 1995-2010, and harsh winter and late spring conditions in 2011. Late Winter Elk Classification Surveys Since 1986, the Working Group has conducted annual classification surveys of northern Yellowstone elk during February or March. A helicopter is used to survey randomly selected sampling units from the lower, middle, and upper elevation sectors of the range. The objectives of these surveys are to: 1) classify a representative sample of the population; 2) estimate the overall sex and age (adult, juvenile) structure of the population; and 3) obtain an index of winter calf survival and recruitment (i.e., calf:cow ratio). The survey was conducted from the ground during winter 1991. No classification estimates were obtained during winters 1993, 1994, and 1997. The 2012 late winter classification survey was conducted on April 2. Due to lower total elk numbers and concentrated distribution a total coverage survey was conducted instead of a random sampling. A total of 5146 elk in 122 groups were classified, including 3081 elk (60%) within Yellowstone National Park and 2065 elk (40%) in Montana (Figures 4 and 5). Age and sex ratios observed for northern Yellowstone elk were 11 calves, 4 yearling bulls (spikes), and 8 adult (branch-antlered) bulls per 100 cows. Calf ratios averaged 11 calves per 100 cows both inside and outside the park. There were no calves observed in the upper elevation sector inside the park. In the middle elevation sector we classified 1280 elk, with a ratio of 8 calves per 100 cows and the highest proportion of bulls, with a total of 36 bulls per 100 cows. The highest ratio of calves per 100 cows was observed in the lower elevation sector inside Yellowstone National Park, where we classified 1769 elk with a ratio of 12 calves per 100 cows. In Montana, we classified 2065 elk with a ratio of 11 calves per 100 cows. Most of the mature bulls were observed in the middle and upper elevation sectors of the park. In the middle elevation sector we observed 275 mature bulls and 46 spikes out of 1280 elk, resulting in ratios of 3
31 bulls and 5 spikes per 100 cows. Overall ratios inside the park were 14 brow-tined bulls and 4 spikes per 100 cows. Bull ratios in the Montana portion of the survey were very low, with only 14 mature bulls observed out of 2065 elk, resulting in a ratio of 1 mature bull per 100 cows. We observed 76 yearling bulls in Montana, resulting in a ratio of 4 spikes per 100 cows. Observed ratios of calves per 100 bulls were similar to those observed during 2002-2005, but lower than the 10 year average of 15.5 (2002-2011), and much lower than the average of 28 calves per 100 cows observed during 1995-2001. The observed ratio of 12 bulls per 100 cows is the lowest observed during helicopter classification surveys. Observed ratios averaged 18.5 bulls per 100 cows during 2002-2011, and 46 bulls per 100 cows during 1995-2001. Spring Elk and Mule Deer Carcass Counts Carcass surveys for elk and deer in Gardiner Basin were conducted on April 20 and 23rd in conjunction with mule deer and bighorn sheep spring surveys. There were no winter-killed carcasses observed during the 2012 survey. Since 1989, the number of elk and deer carcasses counted from the air has fluctuated from 0 to 599 carcasses (Figure 6). The largest numbers of carcasses were observed following the severe winters of 1989 (206 elk and 38 deer carcasses), 1997 (534 elk and 65 deer carcasses), and 2011 (67 elk and 48 deer carcasses). Mule Deer Surveys The status and distribution of mule deer on the northern range is monitored using helicopters to conduct a classification survey during winter and total count, carcass count, and recruitment estimate during spring. These data are used by Montana Fish, Wildlife, and Parks to determine population trends and set harvest levels. Post-harvest mule deer The winter mule deer classification survey was conducted on December 22, 2011 (Figure 7). A total of 826 mule deer were observed and all were classified by age and sex. Bucks were classified as yearlings, 2 point, 3 point and 4 point. Results of classifications were 428 does, 274 fawns and 124 bucks. Of the bucks, we counted 21 yearlings (17%), 66 2-points (53%), 14 3-points (11%), 18 4-points (15%) and 5 unclassified bucks (4%). Population ratios were 64 fawns per 100 does, and 29 bucks per 100 does, including 5 spikes per 100 does and 23 mature bucks per 100 does. This year s survey resulted in the highest buck ratios observed since surveys began in 1990. Observed ratios have averaged 14 bucks per 100 does in Gardiner Basin during 1990-2011, with a range of 7-24 bucks per 100 does. Spring mule deer: Spring mule deer surveys were conducted on April 20 and 23 rd. A total of 1299 deer were observed, which is the lowest number observed since surveys began in 1986 (Figure 8). This is a 29% decrease from last year s count of 1842, and 38% below the 10-year average of 2085. We observed a total of 256 fawns, or 27 fawns per 100 adults. Spring recruitment since 1986 has ranged from 14-57 fawns/100 adults (mean=40 fawns/100 adults, Figure 9). For the Southern Mountains Mule Deer Management Area, the long-term recruitment standard is 30-45 fawns/100 adults. Though survey conditions were good, this winter was mild with little snow remaining at the upper elevations at the time of the survey. We did not detect deer at upper elevations, and green-up was concentrated in the lower elevations, however it is possible that some deer may have begun spring migration prior to the survey, or some deer may not have completed migration into the Gardiner Basin due to mild winter conditions. 4
Pronghorn Surveys The status and distribution of pronghorn is monitored using Super Cub airplanes to conduct a count in spring and classification in late summer. The spring counts have been conducted annually since 1988, with the exception of 1994. Late summer classification surveys were initiated in 1998. A survey to count and classify Yellowstone pronghorn was conducted on September 4, 2012 using a Piper Cub airplane. A single observer counted 243 pronghorn (37 adult males, 177 adult females, and 29 fawns) in 44 groups (Figure 10). This count was similar to the count of 242 pronghorn in 2011, but lower than the count of 297 in 2010. Sex and age ratios observed during the 2012 survey were 16 fawns per 100 adult females (95% confidence intervals = 11-22) and 21 adult males per 100 adult females (95% confidence intervals = 15-27). The number of pronghorn classified on summer ranges used by migrants was 224 (92% of total), compared to 19 (8%) non-migrant pronghorn on the winter range northwest of Mount Everts. An additional 95 pronghorn (11 adult males, 75 adult females, 9 fawns) in five groups were observed in the Paradise Valley (Carbella, West Creek Ranch, Point of Rocks) of Montana. This group was established, in part, by dispersing Yellowstone pronghorn in 2002. Bighorn Sheep Surveys and Harvests During the 2012 survey a total of 378 bighorn sheep were observed, including 226 in Montana and 153 in Yellowstone National Park (Figure 11 and 12). This is a slight decrease the 387 sheep observed last year, but the second highest count since full surveys began in 1995. Though the overall number of sheep observed decreased, the number of sheep observed in Montana increased 10% from 206 in 2011 to 226 in 2012. The number observed in YNP decreased 16% from 182 to 153. The decrease in YNP was due to few sheep observed in the east end of the park. The increase in MT was due to more ewes and lambs observed in the upper elevation Tom Miner area. Classification of observed sheep resulted in 187 ewes, 72 lambs and 118 rams. This resulted in a ratio of 39 lambs per 100 ewes, which is the highest documented since 1995 when surveys began. Lamb recruitment since 1995 has ranged 8-39 lambs per 100 ewes, with an average of 26. Ram ratios for this survey were 63 rams per 100 ewes which is slightly lower than the long term average of 65 rams per 100 ewes. Ram ratios since 1995 have ranged 44 96 rams per 100 ewes. The ratios observed in 2012 differed across the management boundary, with 44 lambs per 100 ewes in Montana compared to 30 lambs per 100 ewes in YNP, and 59 rams per 100 ewes in Montana compared to 70 rams per 100 ewes in YNP. Since 1995, lamb ratios across the boundary have varied but are overall similar, with long term averages of 27 lambs per 100 ewes in Montana and 25 lambs per 100 ewes in YNP. Ram ratios tend to be higher in YNP, with a long term average of 57 rams per 100 ewes in Montana compared to 79 rams per 100 ewes in YNP. In fall 2011, a total of 5 sheep were harvested: 4 rams were harvested in HD303, 1 ram was harvested in HD300, and no rams were harvested in HD305 (Figure 13). Since 2007, rams harvested annually in each area ranged 0 4 in HD300 (average 2 per year), 0 3 in HD300 (average 1.6 per year), and 0-1 in HD305 (average 0.6 per year). Mountain Goat Surveys Hunting District 316 was surveyed for mountain goats September 5, 2012. The objective of the survey was to document mountain goat population and recruitment trends within and adjacent to the hunting district. The survey covered high elevation habitat in the Cooke City area including the Lulu Pass and Daisy Pass area, Mineral Mountain, Miller Mountain, Wolverine Peak, and the ridges running from Mt. Abundance to Cutoff Mountain. Due to concerns with safety and efficiency the survey was conducted by helicopter for the first 5
time, rather than fixed wing aircraft. In most years we have also surveyed Barronette Peak and the ridge system south of Soda Butte Creek from Republic Pass/Woody Ridge west to the Thunderer inside Yellowstone National Park, however due to the increased expense of the helicopter the extent of this year s survey was limited to the Montana hunting district boundaries and extending 1 kilometer within the boundary of Yellowstone National Park. During the survey we observed 44 mountain goats, including 12 kids and 32 adults for a ratio of 38 kids per 100 adults. Of the mountain goats observed, 36 were in Montana and 8 were within Yellowstone National Park. Since 2004 we have observed between 10 and 63 mountain goats in this same survey area, with an average of 41 mountain goats. Kid:adult ratios have ranged from 24 38 per 100 adults, with an average of 29 since 2004. There does not appear to be an increasing or decreasing trend within this survey area, however mountain goats have expanded their range to the south within Yellowstone National Park and overall numbers have increased beyond this survey area (See 2010 NYCWWG report). During the survey we incidentally observed 59 bighorn sheep, including 24 lambs, 30 ewes and 5 rams. Cooperative Wildlife Survey Funding Members of the Working Group have mutually agreed to cooperatively support and fund regularly scheduled wildlife surveys to monitor population trends of elk and other ungulate species on the northern Yellowstone winter range. Member agencies either pay the costs of surveys and other activities directly or contribute funds to the Yellowstone Wildlife Working Group Project Account (Project #53484), which was established by Montana Fish, Wildlife, and Parks to support these surveys and other Working Group projects. Unspent funds in this account are carried forward annually to include any existing funds. Survey expenditures by the Working Group from October 1, 2011 through September 30, 2012 are listed below. Survey Date NPS MFWP USGS USFS Total Elk Count 7 Mar 2012 1,728 $1056 $2,784 Post-season Mule Deer Survey 22 Dec $2,172 $2,172 2011 Spring Mule deer/bighorn 20 Apr $2,500 $1,100 $3,600 Sheep 2012 Bighorn Sheep - North 2 Apr 2012 $900 $900 Bighorn Sheep - YNP 23 Apr $2,100 $2,100 2012 Pronghorn Count & 4 Sep 2012 $888 $888 Classification Elk Classification 2 Apr 2012 $1,800 $1,800 $3,600 Mountain Goat Surveys 5 Sep 2012 $672 $672 TOTAL $5004 $5,700 $2,500 $2,000 $15204 * NPS = National Park Service; MFWP = Montana Fish, Wildlife, and Parks; USGS = U.S. Geological Survey; USFS = U.S. Forest Service. 6
FIGURES.
8
9
10
11
12
13
14
15
16
17
18
19