Adept at cleverly camouflaging itself, the ptarmigan fools predators by turning snow white in order to survive in a harsh, arctic habitat. Simon Lester tracks this elusive species through the seasons.
Like the Scarlet Pimpernel of legend, the ptarmigan is a master of disguise, being the only British bird that changes its plumage three times a year. We may seek them here and seek them there, but the only place it’s possible to see these high-altitude grouse in the UK is above 2,500ft in the Highlands of Scotland.
The truth is, however, that most of us will never catch a glimpse of one of these remarkable birds, as they frequent some of the most inhospitable places known to man. Indeed, they appear throughout the world where Arctic conditions occur, as it is not altitude, but temperature, that dictates their colour and, ultimately, their survival.
Slightly smaller than the red grouse, the ptarmigan relies on camouflage to disappear into the bleak environments it resides in to avoid predation by golden eagles, the wily hill fox, the sharp-eyed raven, peregrine and carrion crow. If flushed, these tough birds are strong fliers — in fact, as the fastest-flying British grouse, they have mastered many aerial tactics to avoid hunting raptors, aided by their large hearts, long wings and tail.
The ptarmigan’s favoured habitat is a hungry place for all its inhabitants, with very little cover in alpine conditions, as the wind-pruned plants have a short growing season before being blanketed by months of snow, all of which has forced Lagopus muta to adapt quickly in order to survive. It is for this reason that it changes its plumage three times: in late autumn, a drop in temperature triggers the moult from which it emerges in a dazzling white winter plumage, only interrupted by black markings on the tail and the bright red wattles and striking black eye stripe of the male. Their feathers stretch from their toes to their nostrils for maximum insulation, as staying still and hunkering down in scrapes behind boulders saves energy. In extreme conditions, the birds will actually fly into deep snow, digging down and pushing it to seal the entrance behind them, which creates a safe, insulated roost.
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With food supply meagre at this time of year, they live on leaves and twigs of crowberry, blaeberry, willow and cowberry. Proficient at scratching through snow and ice to find food, they sometimes get lucky when snow is blown off ridges to expose vegetation to nibble on. However, if conditions get really bad, they will move down to lower slopes where heather is available. To extract the goodness from this woody material, ptarmigan need the grinding action of grit to act as teeth in their gizzards — a full crop is digested overnight.
In spring, they need to change again, as the snow recedes and the breeding season dawns — the most dangerous and critical time of year. As they pair up, ptarmigan lose the luxury of the early- warning system of multiple eyes of the covey: pairs are always more vulnerable and, ultimately, the hen sits on her four to 11 eggs for 25 days at the very same time that all the predators’ demand for prey rises.
Spring highlights their rasping, clicking calls — which gave rise to their Gaelic name, tar machan, meaning croaker — the soundtrack to the increased activity of the squabbling, testosterone-fuelled cocks vying for territories and hens. The size of a territory is directly related to the vigour and aggression of an individual male.
As the snow fades, the cocks remain white during this heightened sexual period, before turning a greyish brown, barred with white and buff. Meanwhile, the hen’s feathering adopts a striking golden-yellow background, heavily marked with bars of black and white — a varied pattern that allows her to disappear into the vegetation as she sits on eggs or broods chicks. She will also often nest near a rock or boulder to protect her home from any adverse weather and to further confuse predators.
After the chicks have hatched and dried off, these hardy little tough nuts venture straight out into the big, wide world. The hen ushers her brood towards food-rich areas — and their first high-protein insects — but, soon, they’ll be feasting on an all-vegetable diet. As day-old chicks, plucky ptarmigan are capable of climbing rocks and running over boulders. Furthermore, in the face of danger, the tiny birds will roll like balls down a slope and disappear into cracks and crannies, hiding quietly until the hen calls them out when the threat has passed. They grow quickly: by 10 weeks old, they are hard to tell apart from the adults.
Both sexes take on their final silvery-grey garb as autumn approaches, when the mottled pepper-and-salt effect allows them to blend in with the lichen-covered screes and boulders of the high glens, which resemble moonscapes.
- A Scottish physician, Sir Robert Sibbald, is responsible for the often confusing silent ‘p’ in front of the bird’s name, which he added in 1684.
- Also known as rock ptarmigan, the species is called snow chicken in the US and thunder bird in Japan.
- The official bird of the Canadian territory of Nunavut, the ptarmigan also features heavily in Icelandic cuisine.
The ptarmigan’s unerring ability to stay motionless makes these illusionists even harder to spot by a passing observer or would-be predator. However, they can sometimes be caught out during transitional moulting periods if the conditions don’t synchronise. Nevertheless, if this happens, they remain astutely ahead of the game and simply move to areas of habitat where their colour of the moment is most cryptic.
Sadly, despite their many wiles, the ptarmigan’s range and numbers are decreasing in the UK, where — despite being a species of ‘least concern’ through the rest of the world — they are red-listed. Although once present throughout the British uplands, they had died out from Cumbria and the higher hills of Wales by the end of the 18th century and from southern Scotland and the islands of Mull and Rhum by 1830, leaving as their only refuge the munros of the Highlands. Because of the hostile and difficult terrain that they frequent, it is very difficult to get a true estimate of their present population. The British Trust for Ornithology believes that there are 8,500 breeding pairs in spring, but the RSPB quotes 2,000–15,000 pairs, which illustrates the discrepancy.
Ptarmigan can still be shot, as this is not thought to be a threat to their population. By contrast, it has been noted that skiing enterprises can have a negative effect on some populations, as do collisions with infrastructure and predators being attracted to areas in greater numbers. The biggest threat to these alpine birds, however, is climate change, as they really can’t move any higher to maintain their way of life.
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