Gray wolf (Canis lupus)
Val Asher, Mike Phillips
Flying D Ranch, MT
Wolves continue to be a polarizing issue in the West, limiting expansion to its historic range.
• Delisted due to recovery: Northern Rocky Mountain distinct population segment (MT, ID, WY, eastern WA and OR, north UT)
• Upon delisting in 2011, wolves became a Species in Need of Management in MT
We aim to understand the ecology of wolves on the Flying D ranch and inform wolf recovery efforts throughout the species’ historical range.
Over the next five years we will locate and identify predator-killed prey and analyze wolf scats to determine predation characteristics of the wolf population on the Flying D ranch. All carcasses will be evaluated for cause of death, body condition, and any predisposition to predation by classifying femur marrow and boiling leg bones and jaws to identify arthritis or injuries. During this time, we will monitor the Flying D’s wolf population and will work cooperatively with the Flying D ranch manager and Montana Hunting Company to track bison herd health, herd size, and the resident elk and deer population. Knowledge of these dynamics and the practicality of living with wolves on a working landscape will be shared by conducting tours for visiting guests.
Supporting Rationale for Objective
Uncertainty over the ecosystem impacts of wolves fosters intolerance for wolves in the west. An abundant prey base on the Flying D allowed the ranch to support what was once the largest pack in MT (24 individuals in 2011), before it split into two packs. The ranch practices an ecologically sustainable management style which also benefits the persistence of large carnivores. We can maintain a healthy wolf population on the ranch by understanding food habits, prey health, and the effects wolves have on ranch activities.
In 2000, we assigned our wolf biologist to assist the USFWS, and later MTFWP, with wolf recovery in Montana. We remain the only private organization ever permitted under the ESA to assist the USFWS with wolf recovery, and it was a notable achievement for us to be involved for over 9 years with the daily implementation of recovery and management. With delisting imminent, we shifted our focus in 2010 to wolves on the Flying D. Wolves first established themselves on the ranch in 2002. In 2011, they were at their highest numbers before splitting into two packs. Both packs made use of the entire ranch (over 113,000 acres) and the bordering forest. Both bison and elk numbers are monitored by the Flying D ranch manager and Montana Hunting Company. In addition to understanding wolves and their effects on ranched bison and wild elk, we have participated in two ongoing studies on the ranch. Both anthrax (B. anthracis) and brucellosis (Brucella abortus) affect ungulates and potentially carnivores through scavenging.
Project Activities in 2018
Wolf population – Despite the loss of the Tanner Pass pack in 2016, the wolf population was back to 24 individuals by summer 2018. The Beartrap pack produced 10 pups this year. Using MTFWP criteria, which uses Dec. 31st survey data as the annual abundance metric, our highest visual count at the end of 2018 was 18 individuals. The Beartrap pack uses the entire ranch, as well as neighboring properties to the north. Four known wolf mortalities occurred in 2018: Three were legally killed during the harvest season and the fourth (SW036F), collared in 2017, was shot, but we were unable to determine if this was a legal “wounded loss” or an” illegal take”.
We were permitted by MTFWP to capture and radio collar one wolf and deployed a GPS collar. A black 4 to 6-year-old female (SW039F) was collared September 14. Our goal is to gain insight on how often the Beartrap pack leaves the ranch and, by acquiring cluster locations, increase chances of finding ungulate carcasses. The collar is programmed to last ~3 years. From September 14 through December 31, 2018, we have acquired 108 days of locations (6 locations/night) equaling 648 total locations.
Food habits – Of the 1,214 carcasses investigated since monitoring began in 2010, 403 were documented as predator kills. 289 were attributed to wolves, with the remainder categorized as coyote (78), mountain lion (9), bobcat (2), bear (6), and unknown predator (18).
Bison are the dominant ungulates on the Flying D, numbering around 3300-5400 individuals. With a bison population almost twice as large as that of elk, we assume that encounter rates between bison and wolves are higher than between elk and wolves. However, wolves are more successful at killing elk or are actively selecting elk to prey upon.
Eight years of scat data was analyzed from 2010-2017. Elk were the main food source for wolves, which was consistent with our kill data. Deer were also an important food source but, because of their small size, are much harder to find. Bison hair was visually identified between adult and bison calves less than ~4 months of age (i.e. red calves). Red calf hair was detected in only 2% of wolf scats, suggesting that this livestock type is not readily predated by wolves.
Prey Vulnerabilities – A generalization of wolf-prey systems is that wolves tend to select prey that are disadvantaged (e.g.,young, old, sick/injured). Environmental traps, maternal behavior and herd health also influence an animal’s predation risk.
We evaluated predisposition to predation using femur marrow of wolf-killed elk and deer. We also examined leg bones for arthritis or abnormalities. Femur marrow is one of the last fat resources the body utilizes. Healthy bone marrow is white, firm, and waxy, while malnourished or diseased animals have marrow that is red, solid and slightly fatty. In advanced starvation, marrow is red/yellow, gelatinous and wet to the touch due to a high-water content. Femur marrows of prey species were collected and categorized as “white/waxy”, “red/firm” or “red/gelatinous.” From marrow collected from 234 wolf-killed elk, deer and moose, 72% were in marginal to poor health.
Another vulnerability is compromised hooves and legs. Of the 332 elk carcasses investigated, 43 had visible deformities and 35 of these were killed by wolves. After boiling the legs, we can detect the calcification and arthritis that has developed.
More data is needed to determine if this is related to injury or other causes. In addition, we have begun to collect and boil legs from all elk mortalities, regardless of visible injury to the hoof or legs, to determine if there are any differences between predator kills and elk that die from other causes.
Education – Information dissemination is important as we learn more about wolves on the ranch. In 2018, we conducted 12 tours and talks on the Flying D totaling ~98 since 2010. We also share our population estimates with MTFWP and data with both the Anthrax and Brucella projects. Finally, we continue to produce monthly and annual reports on wolf activities and food habits.
Proposed Future Activities
With the newly deployed GPS collar, we look forward to learning how often the Beartrap pack leaves the ranch and measuring the success of finding carcasses using cluster data.