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Stoats, Weasels, Martens and Polecats
All about
pine martens
Introducing the pine marten
The pine marten is a charismatic and agile carnivore, native to the woodlands of Britain. Pine martens are part of our rich wildlife heritage and play an important role in keeping our woodlands healthy and balanced.
Pine martens belong to the Mustelidae — the weasel family — which is the largest and most diverse family amongst the Carnivores.
In Britain, their relatives include weasels, stoats, polecats, otters and badgers.
Photos: ©David Baird
Facts about pine martens...
Photo: ©David Baird
Pine martens are present across the European continent with Ireland and Portugal being at the western edge of the species’ range and the eastern edge extending into Russia and the Middle East.
How big are they?
Adult pine martens are similar in size to a medium-sized domestic cat with males approximately 40% larger than females. During the health checks carried out during VWT's Pine Marten Recovery Project (2015 and 2016), the average weight of pine martens was 1.36kg for females and 1.93kg for males.
What do they look like?
Pine martens usually have dark brown fur with a creamy-yellow throat patch known as a bib. Their winter fur is thick and fluffy for warmth and their summer fur is shorter and darker during the warmer months. Every pine marten's bib is unique — much like human fingerprints — and can help us to identify individual pine martens.
Adaptations for climbing
Pine martens are great at climbing trees. A long slim neck and body gives them great flexibility and a long, bushy tail helps them to balance. They also have sharp, semi-retractable claws and ankles that rotate through 180o that allows them to climb up and down the trees. Muscular legs and long feet help them leap from branch to branch.
Pine martens are slow breeders — they don’t start breeding until they are two or three years old, only breed once a year, and usually only have one to three kits (baby pine martens) in a litter.
How do pine martens reproduce?
Pine martens mate in mid-summer but give birth the following spring. Females have ‘delayed implantation', which means that any fertilised eggs are not implanted in the uterus for around 230 days. This strategy ensures that the kits are born during early spring when the weather is becoming warmer and food is more abundant.
When food has been particularly abundant, pine martens can have up to four or (rarely) five kits. When born, each kit weighs around 30g. Their eyes are closed and they have a fine covering of silver hair.
A safe den, which is elevated, warm and cosy, is crucial to the kits’ survival. They will stay in the den for about six or seven weeks and are totally dependent on the mother.
Once the kits are about seven weeks old and they start to explore the outside world, they will need to learn to climb very quickly since their dens are usually high up in a tree away from predators.
Only a small number of juveniles will survive to become adults and breed. Pine martens can live up to twenty years in captivity but are only likely to make it to seven to ten years in the wild, if they’re lucky.
Pine martens are generally solitary animals that live alone in territories, which can vary from around 1km2 to 30km2 in size, depending on the quality of habitat and availability of food.
Young pine martens tend to remain with their mother for at least six months while they learn to find and catch food for themselves. Juvenile siblings will occasionally group up to explore together and share den sites over their first winter.
Once they are adults, pine martens are generally solitary for most of the year and juveniles will start to separate from their mother after six months… though some choose to stay with their mother for longer if she will tolerate them.
Although generally solitary creatures, they can be quite tolerant towards their marten neighbours and there can be some overlap between adjacent territories. Males usually have bigger territories than females and their territories can overlap with those of several females. Where the neighbourhood is particularly busy, they may use scats (marten poo) to mark out their territory boundaries, which often follow linear features like paths.
Britain has a mild and relatively stable climate, but pine martens still vary their activity levels and behaviour according to the seasons. They don’t have large fat reserves and don’t hibernate, so they rely on feeding regularly over the winter to survive. To compensate for colder weather, they reduce their activity levels and sometimes change what they eat to conserve energy.
Pine martens are arboreal, which means they are adapted to life in the trees where they are safer from predators such as foxes.
Where do pine martens live?
Large mixed woodlands with a rich diversity of plants and animals are crucial for pine martens to thrive. Pine martens can use a variety of habitats in addition to woodlands, such as scrub (habitat dominated by bushes and shrubs) and rough grassland, for finding food but woodlands are where they rest and raise their young high in the trees.
Because pine martens need large territories for food and shelter all year round, they require woodlands that are big and well connected. These connections can include the banks of tree-lined rivers and hedgerows but wide corridors of woodland are best for pine martens to move safely through the landscape.
Where do they sleep?
Pine martens prefer to use holes in trees (cavities) that are high enough to keep them safe from predators and big enough for a mum and kits. While cavities in old trees are ideal den sites, these are often missing in our young or coniferous woodland. Pine martens are very adaptable though and can use other places such as rock crevices, underground burrows, buildings (abandoned or occupied), old bird nests, squirrel dreys, log piles and even the roots of blown over trees... but nothing beats a warm, cosy and elevated tree cavity.
Many of the trees in Britain are not old enough to have tree cavities large enough for pine martens to den in so communities are giving them a helping hand by building and installing pine marten den boxes — the bird box equivalent for pine martens.
Photo: ©David Baird
Pine martens are a medium sized mesocarnivore. A mesocarnivore is a mammalian carnivore whose diet consists of 30-70% meat with the rest consisting of plants, fungi and invertebrates.
What do pine martens eat?
Pine martens have a very varied diet and are great at finding food in a range of places. In the trees and bushes, they can find squirrels, birds, insects, fruit and nuts. On the forest floors and in the scrub and grasslands they can find small rodents, amphibians, reptiles, invertebrates, fungi and even carrion (dead animals). In Britain, voles are a particularly important prey item for martens. See FAQs for more information.
Pine martens are adaptable and opportunistic, which means that they change what they eat depending on the season and what is locally abundant. Because they have such a varied diet, pine martens play a vital role in helping to keep a natural and healthy balance of plants and animals in woodlands and forests.
