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Adjacent to Banff National Park is Alberta’s jewel of the Rocky Mountains, the historic Ya Ha Tinda elk. Researchers from the Universities of Alberta and Montana have been working with local biologists for 14 years to determine how changes in the Ya Ha Tinda (YHT) elk population are affected by human and environmental factors.
Once Canada’s largest migratory herd of elk, the YHT population has declined over the past decade to the point where there is concern about the population’s viability. Two types of basic behaviors divide the population on an annual basis. In summer months, some of the YHT elk migrate to Banff National Park in search of high quality forage, while others choose not to migrate. The choice not to migrate is believed to be a choice to avoid wolves. Wolf densities and risk of predation is higher in Banff National Park. Elk calves are most vulnerable to predators during this time, so cow elk are choosing not to migrate in order to protect their calves.
Over time, the number of elk migrating to Banff National Park in the summer has reduced and the number remaining on the YHT winter range year-round has increased. Whether this change in behavior is driven by wolves or habitat is the research question.
This past year, a pilot program was initiated to monitor the survival of elk calves born from migratory and resident elk cows. The research may be able to show a behavioral change in individual cows that influences their recruitment success.
In February and March 2013, 20 pregnant cow elk were fitted with vaginal implant transmitters (VITs) to assist in the capture and tagging of elk calves. VITs emit a signal when a calf is born and are essential for locating neonatal calves in their first days of life. Despite massive flooding in southwest Alberta, 16 calves were captured via ground monitoring of VITs in early summer. Of the 16 calves captured and tagged, five are still surviving as of December 2013. Known mortality causes are attributed to bears, wolves, and one cougar.
This research will continue to improve our understanding of the factors affecting calf recruitment into the migrant and resident YHT herd segments. The long-term, continuous nature of the study allows for a better assessment of the adaptability of elk in response to increasing predator densities, and will give insight to what this means in terms of persistence of the YHT herd. More broadly, such behavioral choices made by ungulates may be an important indicator towards understanding when predator densities or habitat quality have reached the point where wildlife managers should attempt to re-balance the ecosystem.
Photos Credited To: Celie Intering
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