Sublette Moose Project! 2014 Capture Report F67 makes her way back to the willows of Horse Creek after being released from capture. PROJECT BACKGROUND In February 2011, we began research on Shiras moose (Alces alces shirasi) in the Hoback Basin to evaluate demography, movement and nutrition of the largest population of Shiras moose in the continental US. The project continued to evolve in response to potential energy development that may still occur in the region (i.e., 44-7 leasing zone). Although moose are relatively abundant in the 44-7 leasing zone, very little is known about their demography or habitat use. Consequently, we expanded the geographic scope of this project to aid WGFD in understanding and mitigating moose responses to energy development, should it occur. Further, our study is providing comprehensive data on the demographic consequences of nutritional condition, disease and predation for this important Wyoming moose herd. F29 plows through the deep snow of South Beaver Crk. On to the next moose!
DATA COLLECTION This year marked the fourth consecutive capture effort for the project and was funded largely by generous landowners in the study area. The weather was not particularly cooperative this year, forcing us to spread 40 captures over February 10 th, 11 th, 12 th, and 17 th. We recorded calf recruitment for 37 recaptured females as well as 3 newly captured moose along North Horse Creek. The data we collected will inform the USFS-Bridger Teton of moose movement and nutritional condition as they prepare to make a final decision for the 44-7 leasing zone. A B C Similar to previous years, we measured nutritional condition using ultrasonography (A); took body measurements to estimate body mass (B); collected blood samples for pregnancy and Elaeophora testing (C); downloaded location data from GPS collars (D) and added new VHF collars to 25 females (E). Photos by Mark Gocke (WGFD). E D
CAPTURE LOCATIONS Along the Wyoming Range front, moose tend to congregate on winter ranges characterized by expansive willow bottoms in the creeks of Horse, Cottonwood, Beaver and the Green River. These watersheds comprise some of the most significant Shiras moose habitat in the Rocky Mountains, highlighting the need to maintain and conserve their migratory routes and seasonal ranges. With the PXP leasing zone now retired, we have shifted our focus on moose that could potentially use the 44-7 leasing zone. This year, we captured 3 new females along North Horse Creek to augment our sample size for demographic analyses. The table and map below show locations of captured females and our observations of calf recruitment. Each location is labeled with an identification number followed by a c or - (e.g., F42c or F85--) to indicate calf presence or absence at time of capture. Drainage: Numbered Captured: Hoback Basin & Beaver Crk. Green River Horse Crk. Co4onwood Crk. Total 7 6 17 10 40 WYOMING Capture Area
NUTRITION During summer, moose spend much of their time foraging on willow and aspen leaves in an effort to regain fat reserves lost over the winter. Similar to previous years, nutritional condition of adult females was low overall (mean=6.1%), suggesting that poor habitat quality is still resulting in low rates of pregnancy and adult survival. Percent Body Fat Percent Body Fat per Year n=48 n=65 n=40 Below: Dr. Kevin Monteith measures F40 s body fat in Horse Creek using ultrasonography. The image on the right shows where body fat is deposited below the skin. She carried a total of 6.8% body fat, slightly higher than the population average (6.2%), but was not pregnant in 2012 or 2013. Skin layer Rump Fat Year Mark Gocke EMI Imaging Fig. 1: Boxplots showing nutritional condition of adult females per year captured (Black bars represent sample means). Winter severity can create a lag effect on nutritional condition. The winter of 2010/2011 was notably harsh along the Wyoming Range, possibly creating more variation in percent body fat observed in 2012. ANNUAL CALF SURVIVAL Females that gave birth to a calf last summer (June 2013) were monitored for annual calf survival, which was high (75%) see table below for survival proportions according to drainage of capture. This suggests that high calf survival may be compensating for depressed annual rates of pregnancy (<75% annually) and adult survival (<88%). Hoback Basin Drainage of Capture Proportion North Hoback/Beaver Creek: 6/7 Green River: 2/4 Cottonwood Creek Horse Creek: 5/6 South Cottonwood Creek: 5/6 Total: 18/23
WY Game & Fish Commissioner Charles Price helps prepare F40 s release. Sam Dwinnell of the WY Coop Unit prepares a penicillin dose for F13 near Middle Beaver Creek. Maggie Miller and Patty Roberts keep F65 company in Cottonwood Creek. Measurements and samples collected, F67 is released in Horse Creek. Dr. Matt Kauffman stores a blood sample from F40 in Horse Creek. Dr. Kevin Monteith and Gary Fralick release F53 near the rim in the Hoback Basin.
Acknowledgements We are sincerely grateful to the numerous landowners that supported this capture operation, both financially and logistically. Securing sufficient funding is always a challenge and without the generous contributions provided by individuals and organizations, this fourth year of data collection would not have been possible. Many thanks to Finley Resources, Rolling Thunder Ranch LLC, Ricketts Conservation Foundation, Sublette County Outfitters and Guides Association Inc., Wyoming Outfitters and Guides Association, Wyoming Game and Fish Department, Bridger-Teton National Forest, Wyoming Governor s Office, Wyoming Governor s Big Game License Coalition, and Plains Exploration and Production Company. For more information, contact: Brendan Oates (boates1@uwyo.edu) or Gary Fralick, WGFD (gary.fralick@wyo.gov)