In early July, Yukon and Alaskan biologists were waiting on a small miracle: the right conditions to summon an apocalyptic storm of mosquitoes. The biting insects, in turn, would drive tens of thousands of caribou into a massive herd, essential to making them countable from the sky.<\/p>\n
The phenomenon occurs every July, but photographing it from above to obtain a \u201cphoto census,\u201d or population count, is a different story, Mike Suitor, a Whitehorse-based migratory caribou biologist with the Government of Yukon, says.<\/p>\n
Suitor, who has been advising on Porcupine caribou herd management since 2012, says witnessing the migration from a bird\u2019s-eye view is difficult to put into words.<\/p>\n
\u201cIt\u2019s like looking down at an anthill,\u201d Suitor says.<\/p>\n
The spectacle is hard to look away from, but biologists have little time for awe. Flying in fixed-wing planes outfitted with digital cameras, they must capture clear, high-resolution images of the herd. Computer software stitches the images together so biologists can manually categorize every individual with a single dot. The software then sums up the dots and determines the population count.<\/p>\n
It is an undertaking that hasn\u2019t succeeded since 2017, when researchers estimated the herd at 218,000 animals \u2014 the largest population recorded since monitoring began in the 1970s.<\/p>\n
Since then, climate change has further complicated the task. Shifting winds scatter herds into the mountains, where they\u2019re exceedingly difficult to photograph, while smoke from increasingly frequent wildfires obscures the horizon. Some years, biologists can\u2019t even get off the ground, let alone get the shot.<\/p>\n
![\"Aerial](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/10\/PeterMather12548.jpg\"\/)
Researchers have struggled to photograph and count the Porcupine herd since the last photo census in 2017, as the effects of climate change have scattered and obscured the animals. In July, they finally managed to. \u201cIt\u2019s like looking down on an anthill,\u201d Whitehorse-based caribou biologist Mike Suitor says. Photo: Peter Mather<\/p>\n
This year, the urgency was especially high. After seven years without an accurate population estimate, the Porcupine herd \u2014 one of the world\u2019s last healthy migratory caribou populations \u2014 needed to be counted. <\/p>\n
The herd\u2019s calving grounds in Alaska\u2019s Arctic National Wildlife Refuge are currently at the centre of a decades-long fight over oil and gas development. Gwich\u2019in communities on both sides of the border have warned industrial activity in the refuge will destroy the caribou<\/a>. Despite this, Alaska\u2019s state development agency is preparing to conduct 3D seismic testing there for the first time<\/a>.<\/p>\n \u201cWe know how critical [the photo census] is to communities right now,\u201d Suitor says.<\/p>\n With that in mind, biologists doubled the frequency of GPS signals from more than 110 radio-collared caribou \u2014 the small sample of the herd researchers collar to study the larger herd \u2014 and the Alaska team began flying daily patrols. Their persistence paid off.<\/p>\n On July 10, the Alaska Department of Fish and Game announced that<\/a>, thanks to a heat wave which fuelled the right conditions for mosquitoes to swarm and drive the caribou together, they had successfully photographed the Porcupine herd.<\/p>\n Analyzing the images will take months, but Suitor says the achievement is a relief. Many signs suggest the herd is in decline \u2014 a disappointment, but not unexpected.<\/p>\n A recent study that analyzed DNA from caribou fossils dating back 21,000 years projected North American caribou populations could see average declines of 84 per cent<\/a> by 2100, if the planet warms by two to three degrees Celsius. Should greenhouse gas emissions \u2014 created by the burning of fossil fuels \u2014 remain high, the Porcupine herd\u2019s geographical range could shrink by 71 per cent.<\/p>\n It\u2019s a trend communities on the frontlines of global warming have noticed. The Vuntut Gwitchin First Nation of Old Crow, Yukon, live as cyclically as the Porcupine caribou herd they depend on \u2014 and they are just as sensitive to the changing seasons, deputy chief Harold Frost Jr. says. Over the past 20 years, the Vuntut Gwitchin have been living with the daily consequences of what Frost Jr. calls \u201cdrastic changes\u201d in the climate.<\/p>\n While most large migratory caribou herds in North America \u2014 including many in the Arctic<\/a> \u2014 have declined due to pressures from roads and resource extraction, the Porcupine herd has remained relatively undisturbed by these threats. As a result, its numbers have stayed stable \u2014 and even grown. After falling to a low of 123,000 animals in 2001<\/a>, the herd rebounded to a record high in 2017.<\/p>\n Recently, however, there have been troubling signs. Reproductive rates among three-year-old females are dropping \u2014 often an early indicator that a herd is under stress \u2014 and fewer calves are surviving. Even more concerning is data from the 110 radio-collared caribou, most of them females. When a collar stops moving, biologists know the animal has died. Over the past year, only about 80 per cent of adult cows survived.<\/p>\n \u201cWhen you get below 86 per cent, you\u2019re almost guaranteed you\u2019re losing caribou within the herd,\u201d Suitor says. \u201cClimate change is a very significant factor. We hear it from the communities. We see it in the caribou and in their movements. And we\u2019re seeing massive changes in some of these big migratory pathways.\u201d<\/p>\n The question for the Porcupine caribou herd now is: how steep will declines be?<\/p>\n It\u2019s not all bad news: Porcupine caribou herd represents a rare management success, biologist says<\/p>\n Every year, the Porcupine caribou herd makes the longest land migration on earth, traversing more than 4,000 kilometres across tundra, mountains and rivers in the Northwest Territories, Yukon and Alaska to reach its calving grounds in Ivvavik National Park in northern Yukon and Alaska\u2019s Arctic National Wildlife Refuge. Ivvavik<\/a>, in Inuvialuktun, translates to \u201ca place for giving birth, a nursery,\u201d while the Gwich\u2019in people call the Arctic Refuge Iizhik Gwats\u2019an Gwandaii Goodlit \u2014 the sacred place where life begins.<\/p>\n The Porcupine herd is unique for two reasons, Suitor explains. First, much of its range remains largely intact, spared from heavy development, with a few exceptions.<\/p>\n Second, the Porcupine herd was the first in North America to be formally managed through collaboration. The Porcupine Caribou Management Agreement was signed by the federal and territorial governments of Canada, Yukon and the Northwest Territories, and First Nations communities in 1985<\/a>, followed by a 1987 treaty<\/a> between Canada and the U.S. The herd is co-managed by Canada and the U.S., in collaboration with Indigenous communities.<\/p>\n In this way, the Porcupine caribou herd represents a rare success, uniquely positioned to withstand the challenges ahead.<\/p>\n \u201cYou need to have these strong partnerships to realize change, and I think the Porcupine caribou story has been a great narrative around that,\u201d Suitor says, crediting decades of cross-border collaboration.\u00a0<\/p>\n Those partnerships are also facing threats as Indigenous and environmental organizations are gearing up for the next phase of the struggle against the U.S. administration\u2019s agenda of drilling in the herd\u2019s calving grounds in the Arctic Refuge<\/a>.<\/p>\n Laurence Fox, campaigns coordinator at the Canadian Parks and Wilderness Society\u2019s Yukon chapter, based in Whitehorse, told The Narwhal the next phase of advocacy should be guided by Gwich\u2019in communities, who\u2019ve lived alongside the caribou for thousands of years.<\/p>\n Fox points out how the U.S. administration is employing the rhetoric of \u201ca national energy emergency\u201d to move resource extraction projects forward with greater speed, which, they added, is not dissimilar to Canada\u2019s push to pass Bill C-5<\/a>.<\/p>\n Both the U.S. and Canadian governments are attempting to speed up timelines on approving projects and moving major infrastructure and development plans forward.<\/p>\n While protecting the Arctic Refuge from oil and gas development has been a decades-long struggle, Fox says \u201cthe rules of the game\u201d have changed, especially under the current U.S. administration\u2019s leadership. But no matter the gravity of what Indigenous and environmental organizations are up against, Fox says, it\u2019s critical to move forward slowly and methodically.<\/p>\n With this same principle in mind, Canada\u2019s Porcupine Caribou Management Board has worked with Indigenous communities, governments, scientists and policymakers to safeguard the herd\u2019s long-term health.<\/p>\n \u201cWe\u2019re always thinking ahead,\u201d says Joe Tetlichi, chair of the Porcupine Caribou Management Board and a member of the Tetlit Gwich\u2019in who lives in Whitehorse. \u201cAnd the reason we\u2019re thinking ahead is because back in the early 2000s, we watched the George River herd, the Bathurst and the Bluenose East and West all decline.\u201d<\/p>\n The disappearance of other barren-ground caribou herds in North America has been startling. For example, the Bathurst herd in the Northwest Territories plummeted from 470,000 in the mid-1980s to 6,240 today.<\/p>\n These sharp declines motivated Tetlichi and the board, in close collaboration with Indigenous communities, to create a harvest management plan<\/a> that sets clear rules that would limit the number or sex of caribou individuals are allowed to hunt if the population falls below certain thresholds. The plan includes a chart indicating herd status and hunting requirements with levels ranging from green (no restrictions for Indigenous communities, and some for other licensed hunters) to yellow, orange and red (more limited hunting to no hunting at all).<\/p>\n \u201cWe know we have no control over climate change, but we know we have control over harvesting,\u201d Tetlichi says.<\/p>\n Since the plan\u2019s creation in 2010, the Porcupine caribou herd has consistently remained in the green zone. As a result, Tetlichi notes, the plan has never been put to the test.<\/p>\n \u201cIf the herd ever goes down to 45,000 it\u2019s not going to be easy to put our management plan at the plate,\u201d he says, referring to the food security hardships the community would face and the uncertainty of compliance. Despite having a management strategy in place for the situation, the results would not be ideal. \u201cIt\u2019s going to be tough, really tough.\u201d<\/p>\n Today, based on the photo census from 2017 and other indicators, the herd is considered stable. Licensed hunters can harvest up to two bulls, while Indigenous hunters face no limits. Still, Tetlichi stresses, the plan \u201ccovers bases\u201d for the day when the population inevitably declines.<\/p>\n \u201cWe\u2019re taking the bull by the horns and moving forward for the sake of the well-being of the caribou,\u201d he says.<\/p>\n Mosquitoes and warble flies make caribou \u2018go nuts\u2019<\/p>\n Climatic shifts in the Porcupine caribou herd\u2019s range are complex and interconnected, Suitor says. Warmer year-round temperatures are driving more frequent wildfires and increased vegetation growth. Heavy late-winter snowfalls can delay the herd\u2019s migration to its calving grounds. Altogether, the landscape is changing rapidly, forcing the Porcupine caribou to adapt.<\/p>\n \u201cDeciduous vegetation [on the tundra] is growing taller and bushier, which isn\u2019t ideal for migratory caribou that prefer lichen,\u201d Suitor says. That has spinoff effects for attracting moose, which in turn increases wolf predation \u2014 and so on.<\/p>\n Biologists are also asking: could increasing temperatures lead to increased insect harassment of the herd? Suitor\u2019s team has a paper under peer review showing mosquito populations are peaking earlier. If this trend overlaps with calving and post-calving in June \u2014 when calves are still small and vulnerable \u2014 it could lead to increased mortality.<\/p>\n And then there\u2019s the worry about warble flies, bumblebee-sized insects that can travel hundreds of kilometres in search of caribou, buzzing and dive-bombing the herds. The flies lay their eggs in caribou\u2019s fur on the animals\u2019 legs and hindquarters. When the eggs hatch, the larvae crawl onto the caribou\u2019s back, and burrow into their skin for the winter. In spring, they emerge as adult larvae, fall to the ground and the cycle begins again.<\/p>\n \u201cOne warble fly can show up in a big herd of caribou and the caribou go nuts,\u201d Suitor says. \u201cThey hate them. They can expend a ton of energy and during some parts of the summer they will choose habitats without food to try and get away from them, which can affect things like calving rates the next year.\u201d<\/p>\n Suitor and his team have been analyzing 70,000 video clips from collar-mounted cameras. The early results suggest warble fly populations, like mosquitoes, are also peaking earlier in the season \u2014 adding another layer of pressure.<\/p>\n In the Northwest Territories, Indigenous hide tanners have also noticed an increase in hides affected by warble flies<\/a>, who leave pockmark holes.<\/p>\n Christine Creyke, a hide tanner and member of the Vuntut Gwitchin First Nation and Tahltan First Nation who lives in Old Crow, told The Narwhal in May she\u2019s worried about the growing impacts of climate change on the herd.<\/p>\n \u201cWhen I\u2019m working on my hides, I\u2019m always thinking about the environmental changes happening to the caribou and how it\u2019s affecting my work with traditional practice,\u201d Creyke said.<\/p>\n Changes to caribou migration mean big changes for the people who depend on them<\/p>\n The Vuntut Gwitchin of Old Crow are already suffering the consequences of the collapse of another vital mainstay: Chinook salmon. Vuntut Gwitchin deputy chief Frost Jr. says the salmon have disappeared from the Porcupine River, a tributary of the Yukon River, forcing the community to adapt by relying more heavily on freshwater fish.<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/10\/Caribou-Migration-9419-1024x683.jpg\"\/)
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\nThe Porcupine caribou are one of the last remaining healthy caribou herds in North America, but their numbers seem to be declining. Photos: Peter Mather<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/10\/Caribou-Migration-9131.jpg\"\/)
Porcupine caribou traverse a mountainous plain in the Arctic National Wildlife Refuge, where they come to calve in the springtime. The Gwich\u2019in people call the refuge Iizhik Gwats\u2019an Gwandaii Goodlit \u2014 the sacred place where life begins. Photo: Peter Mather<\/p>\n![\"Two](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/10\/CaribouDays-1148736-WEB.jpg\"\/)
<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/10\/Copy-of-CaribouDays-1158850.jpg\"\/)
\nVadzaih Choo Drin, or \u201cBig Caribou Days,\u201d is an annual festival held in the Gwich\u2019in community of Old Crow, Yukon, celebrating the return of the migrating Porcupine caribou herd. This year\u2019s festival was marked by sober discussions of new threats facing the herd. Photo: Michael Code \/ The Narwhal<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/10\/Copy-of-CaribouDays-1170446.jpg\"\/)
<\/p>\n![\"Christine](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/10\/Copy-of-CaribouDays-1171048.jpg\"\/)
\nSharp declines in other barren-ground caribou herds in North America prompted the Porcupine Caribou Management Board to implement a strategy to limit hunting. When the herd is in the green zone, there are no limits for First Nations hunters, who can harvest for meat and hides, like those that Vuntut Gwitchin First Nation and Talhtan First Nation member Christine Creyke works on in Old Crow, Yukon. Photos: Michael Code \/ The Narwhal<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/10\/Warble-flies-in-caribou-hide.jpg\"\/)
Warble flies are more than just a nuisance to caribou herds \u2014 they burrow into the skin of the animals to lay their larvae, which can weaken caribou and leave them vulnerable to infections. Hide tanners have also noticed they leave pockmarks in the animals\u2019 hides. Video: Government of Yukon \/ United States Geological Survey. Photo: Michael Code \/ The Narwhal<\/p>\n
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The Vuntut Gwitchin of Old Crow, Yukon have noted significant changes in the Porcupine caribou\u2019s migratory habits over the last decade and a half. The animals are venturing farther north and east in the winter and returning to the community later in the fall and staying for shorter periods. These changes, in turn, impact the Gwitchin\u2019s ability to hunt and harvest the animals. Photo: Government of Yukon \/ United States Geological Survey<\/p>\n