A warning has been issued over people disrupting the spectacular mating ritual of one of Britain's rarest birds - and threatening its very survival.

The Cairngorms National Park is home to more than 80 per cent of all the capercaillies remaining, with only a few tiny scattered populations found elsewhere in Scotland.

Eight local people, including a community ranger and a gamekeeper, were recently taken on to improve the survival chances of the turkey-sized capercaillies, which have been declining dramatically over the past few decades.

The new workers are part of the Cairngorms Capercaillie Project, which is spearheading community-led action including habitat improvement, to save the endangered species.

But walkers have now been warned that spring is the most vulnerable time for the survival of the bird, which takes its name from the Gaelic for ‘horse of the forest’ due to its distinctive mating call. It is the country’s largest and rarest native grouse species.

The species was wiped out in the UK in the mid-18th century, with the main cause thought to have been a catastrophic loss of its woodland habitat.

Today’s survivors are all descended from Swedish birds, reintroduced to Perthshire in 1837.

READ MORE: DNA project could save capercaillie from extinction

The population reached a high of around 20,000 by the 1970s, but crashed over the following decades to an estimated 1,000 today.

Jocasta Mann of the Cairngorms Capercaillie Project has posted an appeal on the Cairngorms National Park website to walkers.

"Being outdoors in spring is an extra special experience after a long Scottish Highland winter, especially in the Cairngorms National Park, a home to some of the UK’s most impressive – and rare – wildlife," she said.

"This past year, many more of us have been rediscovering the benefits of fresh air, beautiful views and sightings of wildlife we might not previously have seen. Late 2020 saw a post-lockdown surge in visitors to the Cairngorms - and it’s easy to see why. Locals, too, have been taking greater advantage of the amazing trails on their doorstep. So what does this increased activity mean for the Park’s more ‘hidden’ residents?

"Capercaillie were resident in Scotland as early as the last ice age, and it’s easy to picture that, given their remarkable appearance.

"At least 80% of the small remaining UK capercaillie population now live in the Cairngorms National Park. This makes us extremely lucky – but it also means we must take extra care to protect this striking bird, as it is again threatened with extinction and is especially sensitive to disturbance.

READ MORE: Capercaillie's to breed in captivity in bid to boost numbers

"Each spring, capercaillie gather in specific areas of native pinewood to mate. Males will perform an extraordinary courtship display called a lek (old Norse for ‘dance’), strutting about with their heads high and tails fanned, making strangely un-bird-like wheezing and popping and clattering noises.

"If undisturbed, a lek site will host generations of these displays. But if it is disturbed, especially during the very short window where female capercaillie are in season, they might not breed at all that year. Since they’re already incredibly rare in Scotland, each year really does count.

"Capercaillie also prefer very specific conditions due to their diet and nesting needs, which leaves them only a few options for other lek sites if they abandon their usual one.

"Like all ground nesting birds, capercaillie need peace and safety while rearing their chicks. If disturbed even slightly, they might abandon their lek, nest or young and these scattered families may not regroup – chicks sadly will not survive without their mothers.

"Causes of disturbance to capercaillie include visitation by humans – intentionally or not – and accidental encounters with dogs who range off-path.

READ MORE: Loch Lomond's capercaillie in terminal decline

"Capercaillie are a protected species – meaning it’s a legal offence to intentionally or recklessly disturb them while they’re lekking, nesting or rearing young. That’s why it’s so important to familiarise ourselves with the Scottish Outdoor Access Code, so that we know we’re always helping to protect the environment we love.

"Going for a walk with the dog keeps us moving and our canine friends happy – but please be mindful that although your dog might be well behaved and friendly to humans, a ground nesting bird like a capercaillie sees them as a threat and a predator.

"Between April-mid August, when in pine forests please keep your dog on a lead when requested by signage. You can also exercise your dog off-lead in dedicated dog exercise areas, like the one beside Loch an Eilein.

"The Cairngorms National Park boasts a wealth of beautiful trails, and one way we can help capercaillie is by sticking to paths when in forest areas. If we stray off into deep pinewood, it’s possible we will have unknowingly crossed a capercaillie lek site or a nesting area. You can discover more trails and paths in the Cairngorms on our website.

"Trust us, we’d love to spot a capercaillie on our daily walks. But for now if we leave them in peace and give them the space they need to flourish, perhaps one day in the future that might just become a reality!"