Pine marten

Scientific name: Martes martes

“But the marten laughed. And once again it sounded like an old woman’s laughter.”
– Cornelia Funke, Inkdeath

Arboreal and agile, pine martens make themselves known by leaving behind blue or red scat in the summer, when a diet of bilberries, rowan berries, and blackberries transforms their colour!

Taxonomy chart

Animalia – Chordata – Mammalia – Carnivora – Mustelidae – Martes – M. martes

Conservation status: UK Red List

GB: Least concern

England: Critical

Scotland: Least concern

Wales: Critical

Global: Least concern

Summary

Diet: Mixed. Hares, squirrels, small rodents, birds, beetles, berries, carrion, eggs and fungi.

Habitat: Mainly woodland: coniferous, mixed, and deciduous.

Size: Weight: males 1.5-2.2kg, females 0.9-1.5kg. Size: males 51-54cm with a tail 26-27cm, females 46-54cm with a tail 18-24cm.

Lifecycle: Live up to 8 years. Litters of 1-5 young marten born in early spring, staying with their mother for 6 weeks.

Conservation concerns: Lack of habitat availability and connectivity, poisoned baits and traps.

Terminology

Scat: The name for pine marten faeces.

Geography

In Scotland, most pine martens are found in the Scottish Highlands and Grampians, with isolated populations in southern Scotland. They can also be found in pockets of northern England and northern Wales, as well as the New Forest. They are widespread and relatively common in Ireland.

Although they occur in a wide range of habitats, pine martens prefer well-wooded areas with plenty of cover, including coniferous, mixed, and deciduous woodland. They favour areas with mature trees with holes and cavities in order to raise their young.

Biology

Pine martens can grow to around 51-54cm for males and 46-54cm for females, with tail sizes of 26-27cm and 18-24cm respectively. Males weigh up to 1.5-2.2kg and females 0.9-15kg.

Covered by a dark brown fur with a yellow-white patch or ‘bib’ extending down their throat and chest, pine martens have pale-outlined ears and long, fluffy tails. Their coat is thinner and darker brown in summer, whilst in winter, it grows thick and is a paler, medium grey-brown. Each pine marten’s bib is uniquely shaped, meaning they can be identified by their bib’s pattern. Pine martens also have semi-retractable claws, making them great climbers.

Pine martens can live up to 8 years. During the mating season, usually solitary pine martens will come together to breed, emitting a cat-like ‘yowling’ sound. They usually produce one litter a year of 1-5 young, with the cubs being born in March and April in dens. The cubs then stay with their mothers for 6 weeks – their fathers not having any involvement – before emerging from their dens. At 6 months old, they are fully-grown, but they usually don’t mate for the first time until 2 or 3 years old.

Ecology

Pine martens enjoy a variety of food, including squirrels, small rodents, birds, beetles, fruit, carrion, eggs and fungi. Small mammals are a main part of their diet, making up at least 40%, but as opportunistic feeders, pine martens will also take birds and their eggs, predate on corvids such as jays and magpies, and occasionally predate animals as large as hares. Fruit and berries make up a substantial part of their diet in summer, including from rowan, cherry, hazel, bilberry bushes and brambles– so much so that these often change the colour of their scat to blue or red! Lastly, pine martens have been recorded predating more on invasive grey than native red squirrels, as grey squirrels are less furtive and spent more time on the ground foraging.

Pine martens build dens in hollow trees or the fallen root masses of Scots pines – which is probably what earned them their name. Alternatively, cairns and cliffs covered with scrub are frequently used as den sites. Pine martens have territories that vary in size according to habitat and food availability. For males, these are about 10-25 square kilometres, and for females, these are around 5-15 square kilometres. They mark their territories with scat deposited in conspicuous places, such as forestry trails. Pine martens are also mostly nocturnal and solitary, making them hard to spot.

Conservation

Pine martens and their dens are fully protected by the Wildlife and Countryside Act (1981); they must not be trapped, sold or disturbed except under licence from Scottish Natural Heritage, the Countryside Council for Wales, or Natural England. Despite this legal protection, poisoned baits and traps, often set for hooded crows and foxes, still probably account for many pine marten deaths each year. Others are also shot at hen houses, and some are killed when mistaken for mink. In addition, estimates show that at least 20% of a habitat needs to be woodland to support a pine marten population, which means habitat availability and connectivity can also be a conservation concern.

Studies have found that pine martens are more likely to predate on grey squirrels than red, meaning red squirrels might benefit from their presence by being able to reestablish populations in areas where there are pine martens. However, other research suggests this effect is only present when there is a very high density of pine martens.

History

Pine martens have been here since the end of the last ice age, when they were our second most common carnivore. Until the 19th century, they were found throughout much of mainland Britain, the Isle of Wight, and some of the Scottish islands.

Pine martens played a significant part in history and folklore across America, Europe and the British Isles. In Native American folklore, pine martens are portrayed as brave heroes, as well as symbols of determination, skill, and luck. In Croatia, their fur was used as a unit of currency during the medieval period, whilst now, the Croatian currency the ‘Kuna’ is named after the pine marten, whilst coins are also engraved with their image.

In Ireland, the pine marten is known as ‘cat crainn’, meaning ‘tree cat’. In Scotland, Highland shepherds have long accused pine martens of killing sheep by seizing them by the nose and eating them until the sheep dies a lingering death. This myth was very prevalent in the Victorian era, with pine martens treated as ‘the scourge of the glen’. They were also believed to have a poisonous barb hidden in their tails.

Unfortunately, these beliefs led to persecution from gamekeepers and hunters, and alongside habitat fragmentation, this led to the pine marten’s drastic decline. By 1926, the main pine marten population in Britain was restricted to a small area of north-west Scotland, with small numbers in north Wales and the Lake District. They have since started spreading again with help from conservation and translocation efforts.

How to identify

Tracks: Tracks are very similar to other carnivores and can easily be confused with polecat and mink, as they are also five-toed and of similar size. Their width is 3.5cm, and their length is 4cm.

Scat: Scat is usually deposited singly and often contains hair and bone. They can be variable in size, 40-120mm in length and 12mm thick. They are blackish but sweet smelling, like violets when fresh.

Surveying period: May to September, especially June to August when scats are most abundant. As well as surveying for scats, hair tubes and remote infra-red cameras can be used.

Frequently asked questions

Yes, pine martens will eat squirrels, and some studies show they are more likely to eat greys than reds.
Pine martens can kill chickens. To prevent pine martens from killing your chickens, it is recommended to use electric fencing or a hen house.
No, pine martens do not hibernate.
No, pine martens are not dangerous to humans.
Pine martens are largely nocturnal but can be active during the day.

Confusion species

American mink (Neovison vison)

Mink have a dark brown coat with a white chin, compared to the pine marten’s cream-yellow bib. Mink have a blunt tail, whilst pine marten tails are fluffier. Minks’ ears are also smaller and less conspicuous than those of a pine marten.

Polecat (Mustela putorius)

Polecats have patches or a band of pale fur above their eyes and around their mouths, which creates a bandit-faced appearance, whilst pine martens have a dark brown face. Polecats have a blackish coat, with a cream underfur that shows through, whilst pine martens have dark brown fur with a cream-yellow bib. Polecats’ ears are smaller and less conspicuous than those of pine marten.