This is a tale of two species.

Yukon government biologists are reporting steep declines in the mountain sheep population in the Kluane region, while the lesser-studied mountain goats seem to be increasing.

Kyle Russell, a biologist with the Yukon government, spoke to the Star last Tuesday.

Throughout the Kluane region, researchers have been noticing a trend for the last two years of a declining Dall sheep population.

Specifically, there have been fewer lambs being born and surviving, Russell said.

The trend was first noticed in 2022 as regular surveys were taken post-winter, he said.

More surveys in 2023 reinforced what the first survey was seeing.

The surveys undertaken this year were expanded beyond the 2022 surveys, including the well-known Sheep Mountain area, he said.

In some places, the decline was “severe,” he said.

“It was quite a significant decline,” according to Russell.

Prior to 2022, the last surveys in some of the six sheep management areas were done in 2016.

The culprit, biologists suspect, is the heavy snow the southwest Yukon has seen in the last three years.

The winters of 2020-2021 and 2021-2022 were particularly heavy, Russell said.

In some place, the snow was 400 per cent greater than normal.

He and his colleagues are speculating the sheep couldn’t handle the increased snow-load as well as they might have.

The exceptional winters also fall within the sheeps’ normal cycle of crashing populations that happens on an eight- to 11-year basis, Russell said.

It’s similar to what happens with the snowshoe hare population, which has a well-known boom-bust cycle when it comes to their numbers.

Russell said there are some indications the two species have crashes at similar times, but it’s a poorly-researched subject.

Snowshoe hares in the southwest, particularly in the Whitehorse region, are just starting to rebound.

Interestingly, the reverse appears to be true for mountain goats, Russell said.

While they aren’t as well studied as the Dall sheep, there are indications the goats are weathering the winters of the last three years far better than the sheep are, and are expanding their range further to the east, which is more associated with sheep country.

While it is mostly a natural phenomenon and environmental matter, Russell said biologists are still hoping to lend a hand to the Dall sheep.

There are various tools biologists are looking to use to give the sheep a break, in particular voluntary closures to hunting, camping and hiking in prime lambing areas.

That’s when sheep are particularly vulnerable, and the mortality rates of lambs is higher.

Russell is advocating the establishment of a sheep management plan for the region, in co-operation with Indigenous governments and the public.