Deer on the move
The deer’s muted brown colouring makes it difficult to see in the dappled morning light. This is how deer hide from predators, and also how they make this kind of operation tricky.
The tranquilizing drugs take effect slowly. Joined by project volunteer Jerry Duhamel and park official A.L. Horton, the team are like covert operatives silently closing the perimeter around the doe as she becomes drowsy. To scare the deer now could cause adrenaline to course through her body, temporarily overriding the drug, and allowing her to bolt from sight, so they move as silently as the icy, sloping forest floor allows.
After stabilizing the deer, the team fits her with a collar that will allow them to follow the doe’s movements through the park. It’s part of a joint project between Parks Canada and University of Calgary designed to get a better understanding of deer distribution, and trends in deer population size in Jasper National Park.
Both mule and white-tailed deer are being studied, although the majority of those currently collared are mule deer. Preliminary data has just started to roll in, but reveals some surprising results. Deer previously thought to be from different populations may actually be the same deer that have migrated long distances.
“One [deer] was caught at Jasper Park Lodge, and it migrated up to the northern part of Maligne Lake,” says Arnison. “Another individual went from sixth bridge to the very south part of Maligne Lake. No one had any idea that was going on.”
Arnison says it’s not yet clear whether the deer are moving in groups, or as individuals, and this has raised questions about how to define deer populations in the park. “Right now we just have data for individuals, but hopefully, as we put out more collars, we can get a [better understanding of this] over several years.”
Complicating matters is the fact that historically, the mountains and foothills were not habitat for white-tailed deer. The species has been expanding westward and northward from its traditional range in the prairie, parkland and southern boreal zones. “It’s believed they are moving north because of climate change. We’re trying to understand how that might be influencing other species,” says Arnison.
One species that might be affected by expanding deer populations (both white-tailed and mule) is caribou. “If deer populations are exploding as fast as we think they are, then wolves might be coming [more frequently] into the area.” Arnison says this in turn may increase the frequency with which wolves encounter caribou.
Increasing deer populations may also allow wolves to maintain their numbers despite a declining elk population. Trends in wolf diet will be the subject of a research project soon to be carried out by a colleague of Arnison’s at the University of Calgary.
Volunteers have been integral to the success of the study. The majority of the project deer have been caught using clover traps. These are large metal-gated traps that are baited with hay. Volunteers help with monitoring the traps, and handling the animals during the collaring procedure. “It’s been really rewarding to work with people external to the project,” says Arnison, who hopes Jasper residents will be interested in volunteering again next year.
For now, capture work is finished to allow female deer to carry out later-term pregnancy and fawn-raising without hassle from humans. Parks Canada officials will continue to download deer locations over the summer and fall months. Given the long forays collared-deer made into the Maligne Valley last year, Arnison says it will be interesting to see whether they go back to those areas, and over time understand why they choose them.