North Yukon regional biologist Mike Suitor is privileged to be the bearer of great tidings this fall. The animals of the Fortymile caribou herd, which had been found almost exclusively in Alaska for many years, have expanded into former Yukon ranges, as well as places where their presence has never before been documented.
“It’s a landmark moment,” says Suitor of the tens of thousands of these barren-ground caribou that swarmed into the territory this autumn. As recently as the 1970s, the herd had been knocked back to somewhere around 6,000 to 8,000 animals.
“They climbed slowly from that time to 1993 when they were at about 22,000 animals,” Suitor adds. “But we weren’t seeing the caribou coming back to the Yukon really – a few animals, but nothing serious, not compared with historical records of herds of caribou swimming rivers and stopping ferries.”
It’s been hugely rewarding for Suitor and his colleagues to witness such results after years of international effort. “The Fortymile herd has been the subject of some of the most significant recovery efforts of any herd in Yukon and Alaska,” says the biologist. In the mid-1990s, recovery initiatives were put into place and “a whole pile of action started on both sides of the Yukon/Alaska border.”
Those actions included a ban on hunting the herd by licensed hunters, a voluntary closure of harvest for Tr’ondek Hwech’in citizens, and some focused intensive wolf-control efforts in calving areas, along with plenty of other habitat research work.
“Some of this came out of the Tr’ondek Hwech’in Final Agreement – everything from, ‘Let’s try to understand how much development footprint there is on the landscape,’ to ‘Let’s quantify how much lichen cover there is across the landscape,’” says Suitor. Lichens, of course, are the primary winter food for these mammals.
The objective of recovery was to return the herd to its historic range, primarily in the Yukon. That range covered a swath of land from Fairbanks to Lake Laberge. In fact, oral records of the 1920s recall many Fortymile caribou ranging all the way down to Lake Laberge. In the 1950s there was yet another spike that saw the animals moving into the Dawson Range and Mayo.
One of the fascinating, and challenging, aspects of the Fortymile herd expansion is how it breaks into sub-groups, with some animals heading into the Dempster Highway corridor, others moving south toward White River, and others hanging around the Top of the World Highway. These movements bring them into contact with other barren-ground caribou, those of the Porcupine herd, as well as mountain caribou of the Hart herd.
It can be difficult to tell animals of different herds apart. Fortunately, Suitor and his colleague, wildlife technician Martin Kienzler, have access to some essential technology that includes a Cessna 206 aircraft and two types of radio collars.
Each collar works on its own frequency, Suitor explains. When the biologists fly over the herd, they can determine which individual animals they are dealing with by tuning into their assigned frequency. The beeping noise gets louder as they approach the animal, and fades as they leave the animal behind.
When interviewed by Your Yukon earlier in November, Suitor had just returned from flying over the Dempster Highway region, where he observed thousands of Fortymile caribou. The researchers try to determine the number of caribou in an area by the number of collars they tune in and visuals they get of caribou during the flights. “So if we were to hear 30 per cent of the collars, we would assume that 30 per cent of the herd is in the area,” he says.
“It’s tricky, though. We’ve flown over one collar and there have only been 10 animals around it. We’ve flown over other groups in which there’s one collar and 2,000 animals.”
Despite the anomalies, the scientists do draw rough estimates when assessing the number of animals moving into an area. “We’ll never say, ‘It’s 35,200 animals,’” Suitor says. “What we’ll say is, ‘It’s somewhere in the ballpark of 30,000 to 50,000 animals.’ From a management perspective that’s all we really need to know.’”
When it comes to barren-ground caribou, Suitor and his colleagues deal with some very large numbers, sometimes into the hundreds of thousands, especially when the caribou are dropping calves. They all get together and drop them at the same time, he says. The idea is that predators, such as golden eagles and wolves, will be overwhelmed by the numbers and unable to consume an entire generation of youngsters.
The mountain caribou, such as those of the Hart herd, practise the opposite tactic when calving. It’s called “spacing out.” Each calf is dropped far from the others, the idea being that a predator can’t get from one calf to another readily, and so many more are spared.
The Fortymile moms tend to calve about May 21. The Porcupine herd calves about a week later. Fortymile caribou move into mountains ranges west of Eagle to calve. After that they tend to travel widely in summer, but for winter they move into forested country. The Dawson area provides good winter range, because the animals encounter fewer heavy snowfalls and the snowpacks along ridges are often blown away by wind, exposing the lichen bounty and making it easier to get at.
“This winter range tends to be quite large,” says Suitor. As the herds grow, they stretch their legs. “When recovery work was taking place, many biologists predicted that when the herd reached about 50,000 members again, it would expand into the Yukon. And guess what? That’s just what happened.”
For Suitor, the excitement includes the collaboration involved in the recovery work. “Obviously, we don’t work on this alone,” he stresses. “We work with a lot of partners in Alaska, N.W.T. and the Yukon, with different First Nations and the Inuvialuit, of course.
“The beautiful thing is that strong human relationships have developed … Diplomacy works.”
This column is co-ordinated by the Yukon Research Centre at Yukon College with major financial support from Environment Yukon and Yukon College. The articles are archived at http://www.yukoncollege.yk.ca/research/publications/newsletters_articles