Exclusive: Ecologists say there are early signs that the population is recovering in remote forests
It is a discotheque for Britain’s biggest type of grouse. Before dawn, male capercaillie will begin their courtship rituals, their black tail feathers erect and fanning out, chests puffed out, their heads thrust high into the cold spring air.
Their dancefloors are forest clearings in the Highlands which echo the males’ wheezing, popping and clattering mating calls. Often perched in surrounding pine trees, hens will carefully watch as their potential mates compete to win their affection.
Known as leks, the Old Norse word for play, these meetings are scattered across clearings in pine forests in the Highlands. Many are discreetly monitored each spring by ecologists, who have been increasingly fearful that capercaillie are again heading for extinction in the UK.
The capercaillie (Tetrao urogallus)
What is it?
The biggest member of the grouse family, it thrives in pine forests. Males are roughly the size of a turkey, weighing up to 5kg. Hens are smaller and slender, weighing 2.5kg at most.
Where do they live?
In the Scottish Highlands, where they feed on blaeberries, shoots and stems, in patches of the Pyrenees, northern Europe and northern Russia across to Mongolia
How many are there?
Only about 540 survive in the UK, chiefly in the Cairngorms, due to disturbance, loss of suitable forests and climate change but they are plentiful across continental Europe, where up to 2m live
Where does its name come from?
The name capercaillie is a corruption of the Scottish Gaelic capall coille, meaning horse of the forest
For the last eight years, capercaillie have been in consistent decline. Last September, Scottish conservationists warned that their population had fallen to just 542, half their number in 2015-16. In many areas where they were once abundant, capercaillie are on the brink of disappearing.
But on Speyside in the Cairngorms and in a forest north of Inverness ecologists working for Forestry and Land Scotland, the government agency, believe they have found early signs of recovery.
Kenny Kortland, an experienced wildlife ecologist for Forestry and Land Scotland (FLS), said that four of its forest lek counts this year had shown an increase in capercaillie numbers, the first time in recent years.
In April and May in Strathspey, the area that includes the forests of Rothiemurchus and Glenmore, FLS detected 58 male capercaillie, an increase on the 52 seen in 2020, with a conservative estimate of 30 hens watching the displays.
In Tain, north of Inverness, staff detected 11 males and at least seven hens – the highest number there since 2011. They may be bucking a trend of wholesale retreat across every other capercaillie range save Speyside. Kortland said it made him hopeful numbers would grow next year.
“It’s more difficult to count the hens, as they’re often up on the branches or flying around to get the best view of the displaying males,” he said. Hens only appear on the leks for a week. “It’s important to have as many hens as possible because capercaillies don’t pair up, only a few of the males mate with the hens.”
Kortland said these findings are particularly satisfying as the forests involved are also heavy in predators, which include birds of prey such as goshawk, pine marten, crows and foxes. That suggests capercaillie can survive in a rich, balanced ecosystem.
“The predator community has reassembled,” Kortland said. “Yet capercaillie are able to persist and in fact increase. We may have to accept a lower density of capercaillie but based on the evidence so far, it suggests they can coexist in the presence of predators. So that’s really quite exciting.”
It remains unclear whether Kortland’s data will be mirrored by findings from other sites: the Cairngorms capercaillie project, which includes FLS involvement, is due to publish all its lek count figures later this month, which may show a more complex picture.
Like other grouse species, capercaillie populations can naturally fluctuate year on year, depending on the impact of spring weather on breeding; on vole populations – if pine martens cannot feed on vole, they switch to capercaillie chicks; or from human disturbance.
Cairngorms national park has enforced stricter rules on tourists and local people, with some forest paths shut temporarily or rerouted to protect lekking areas. They have been told to keep their dogs on leads, and to avoid hiking and mountain-biking off designated trails.
Deer fences known to kill capercaillie are being stripped out and forests are regenerating naturally. Some landowners, including FLS, use diversionary feeding too to directly feed some predators, reducing the threat to capercaillie.
In Perthshire, the Aberdeenshire catchments of Deeside and Donside, in Moray and Nairnshire to the north-east, the populations are in low single figures, putting them on the brink of local extinction. However, Scotland’s aggregated data suggests the total population has stabilised over the last two years.
For Scotland’s conservation movement, losing capercaillie would be a humiliation. The current population is the remnant of a reintroduction from Sweden in 1837, the UK’s first, after they were hunted to extinction. In the early 2000s, the Scottish population was estimated to be 2,000.
If Kortland’s findings are replicated by other agencies, it may be another indicator that Scotland’s broader rewilding efforts are succeeding.
Earlier in June, NatureScot, the government conservation agency, said beavers were now spreading rapidly. It estimates that there are more than 420 beaver territories across Scotland, involving about 1,500 individuals. A decade ago only a few dozen were thought to be in the wild – the result of unlawful and accidental releases from private collections.
Several days ago, it emerged that captive-bred wildcats – a native species brought to the edge of extinction in the UK – are now being released into very carefully selected sites in the Cairngorms. “We’re slowly piecing these ecosystems back together,” Kortland said. “The more species we can have, the more robust these ecosystems become.”