Only two of nine caribou calves that were raised in a local maternity pen survived the winter, but stakeholders are hoping for better results for year two.
“Those numbers are pretty close to the background rate of wild calf survival,” said caribou researcher Rob Serrouya. “We were expecting and hoping for higher calf survival, but we also faced the lowest snow year in the last decade that we’ve been researching caribou, maybe longer.”
That snow pack, which included several rain-on-snow events that led to hard surface conditions at higher elevations, likely made it easier for wolves to travel and prey on caribou, said Serrouya.
“Going into the winter, we had about 66 per cent survival of the calves, which was huge, it was higher than expected,” he said.
Unfortunately, the great start didn’t last over the winter, which Serrouya speculates was due to the snow conditions.
“Normally, for about a third of the year the wolves and the caribou are completely separate,” he said. “Normally we don’t see much caribou mortality over the winter.”
The upside, he added, is that all the captured adults survive.
“At the end of the day, if you increase your adult survival from 80 to 100, you’re having as much if not more impact on the population trajectory than if you improve calf survival,” he said. “If that is due to a pen effect, then there’s actually a positive out of that.”
Last year, Revelstoke Caribou Rearing in the Wild, captured 10 adult females and two 10-month-old calves. They were brought to a maternity, where nine cows gave birth. The cows and their offspring spent several weeks in the pen before being released into the wild.
As of March, two calves were confirmed alive, one was killed by wolves and the other nine were no longer with their mothers and presumed dead.
RCRW recently completed the capture of 18 female caribou and one calf to start year two of the project. (Article continues following the video)
Seven of the eight caribou that were captured on March 26 are confirmed pregnant, while the status of the ones captured April 2 is still to be determined.
Serrouya said the results of year two will provide “a more definitive test because it will have a higher sample size and hopefully normal winter.”
“If it doesn’t work with a normal winter, than the method may not work,” he said. “If it works on a normal winter, then we’ll see this one year is an anomaly.”
RCRW aims to provide a safe place for the caribou to give birth and raise their young during the critical early weeks of their lives before they are released in to the wild. The group recently received funding to run the program for another four years.
“We didn’t make things worse, and we probably made things better,” said Serrouya.
RCRW is a partnership between numerous local stakeholders, including the Revelstoke Community Forest Corporation, North Columbia Environmental Society, Revelstoke Snowmobile Club, Mica Heliskiing, Splatsin First Nation, Columbia Mountains Caribou Research Project, the Province of B.C. and Parks Canada.
Other supporters include Downie Timber, the Fish & Wildlife Compensation Program, Columbia Basin Trust, Shell Canada, Golder & Associates and Selkirk Tangiers Heliskiing.