The single-engine Cessna skimmed less than a thousand feet above the southern Selkirk Mountains located between northern Idaho and British Columbia, Canada where a small sub-population of Southern Mountain Caribou are known to live. Norm Merz, a biologist from the Kootenai Tribe of Idaho, and Brittany Morlin, a biologist for the U.S. Fish and Wildlife Service in Idaho, both peered out the windows searching for sign of the South Selkirk sub-population of Southern Mountain Caribou.
“It was sunny with no wind, perfect flying conditions for the month of March,” Morlin said. The Cessna accelerated to the high basins then started circling while its occupants continued to search. Then suddenly, there they were, winding trails of caribou tracks visible in the snow.
Southern Mountain Caribou are big animals, but difficult to spot in the vast landscapes they call home, let alone from a small plane. Surprisingly, their tracks break up the smooth snowy surface and are easy to identify. Caribou have large, concave hooves that spread widely like snowshoes to support them as they seemingly float over the snow. They are the only member of the deer family in which both sexes grow antlers. Nicknamed, “Gray Ghosts,” the Southern Mountain Caribou are secretive, shy and rarely observed in these large, high elevation landscapes and are therefore described with phantom-like qualities.
The Cessna continued to follow the line of tracks in the snow which finally led them to the caribou, basking in the sun, but still difficult to see on the background of white. The pilot circled around the basin so that Morlin and Merz could count the animals several times to be sure of the number. They saw three caribou—and only three.
“It was an eerie feeling, even though it was absolutely gorgeous out there,” Morlin said. The Cessna took the crew to search other basins that were known to be used by caribou in the past. Tracks of other wildlife such as mountain goat were observed but no more caribou. The Cessna returned home with the somber news. Biologists from the B.C. Ministry of Forests conducted additional surveys in the weeks that followed confirming the count of three for the South Selkirk sub-population of caribou.
What happened to the caribou?
In recent years, the number of caribou near the international border has decreased precipitously. In March, biologists conducting the 2018 annual count reported that the South Selkirk sub-population is down to three individuals from the 11 animals reported in 2017. All three remaining caribou were confirmed female. From an obvious biological standpoint, the significance of a female-only unit is clear: no more caribou calves.
When the South Selkirk sub-population was listed under the Endangered Species Act in 1983, approximately 25 animals called this borderland area home. Influxes of translocated animals in the late 1980s and late 1990s appear to have helped the herd reach 46 animals in 2008-2009.
Forest fragmentation, human disturbance, and increased predation are critical pieces of information in understanding the South Selkirk sub-population conservation puzzle. Caribou overall have an interesting and sometimes confusing genetic structure structure
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Learn more about structure . There are five subspecies of caribou; woodland caribou is one of those subspecies. Southern Mountain Caribou is the southernmost distinct population of woodland caribou and the South Selkirk sub-population (or herd) represents the southernmost extent of the larger Southern Mountain Caribou population.
Southern Mountain Caribou are unique in that they occupy mountainous regions of the inland temperate rainforest, extending from east-central B.C. to the inland northwestern U.S. Southern Mountain Caribou do not make the long distance migrations of other woodland caribou. Rather they migrate vertically up and down the mountains several times a year to meet their biological needs. They inhabit forested areas with deep snowfall and feed solely on tree lichen in the winter.
The South Selkirk sub-population is the only sub-population of the Southern Mountain Caribou that range into the coterminous U.S. However, these animals are just one of 15 sub-populations that contribute to fewer than 1,200 remaining Southern Mountain Caribou. Sub-populations of Southern Mountain Caribou are typically comprised of multiple herds, but in the case of South Selkirk sub-population, only one herd represents the sub-population.
“The long term survival of Southern Mountain Caribou are dependent on an arrangement in which animals from multiple herds can interact and this not happening across the range of Southern Mountain Caribou and even less so within the South Selkirk sub-population.” said Morlin.
Saving the Southern Mountain Caribou
While the future of the South Selkirk sub-population is uncertain, there is hope for recovering the overall Southern Mountain Caribou population. An international technical working group composed of federal, state, and provincial agencies, organizations, and First Nations and Tribes are working together to address the threats that affect the South Selkirk sub-population. This includes continuing to conserve habitat within the management area and investigating future opportunities to re-establish the sub-population.
This working group is putting together a management plan for the South Selkirk sub-population that will help to inform recovery planning for Southern Mountain Caribou. The U.S. Fish and Wildlife Service is in the process of expanding coordination with Canadian partners to develop a unified strategy that considers the needs and contributions from all remaining sub-populations of Southern Mountain Caribou.
“Southern Mountain Caribou in Canada are also struggling,” Morlin said. “stabilization of the larger sub-populations and reconnection of the habitat in between them will ensure the long-term survival of Southern Mountain Caribou.”
The goal is clear: to continue to work together across international borders and to help recover the Southern Mountain Caribou. The “Gray Ghosts” may be in serious decline, but it may not be too late for recovery.
Update
This story was originally written in 2018. Since then, the Fish and Wildlife Service published a final rule in October 2019 designating the southern mountain caribou distinct population segment (DPS) of woodland caribou as endangered under the Endangered Species Act (ESA). This action amended the previously listed entity by defining the DPS, which includes the U.S.-Canada transboundary South Selkirk subpopulation and 16 additional subpopulations of caribou in Canada. Of the 17 subpopulations identified, eleven subpopulations within the DPS are considered extant.
Subpopulations at the southern extent of the range are among the six subpopulations considered as confirmed or probably extirpated. The last known caribou in the southern mountain caribou DPS population from the South Selkirks and four caribou from the South Purcells were translocated to the larger Columbia North subpopulation using a soft release approach in early 2019.
The Selkirk Caribou International Technical Work Group (SCITWG) finalized the South Selkirk Caribou Management Plan in February 2019. Participants in the plan's development included Tribal, local government, State, and Federal representatives. The Service is continuing to work toward recovering the southern mountain caribou DPS population and recognizes the importance of bi-national and cross-sovereign collaboration with Canada on the potential development and implementation of a recovery plan.
