Pine marten

The pine marten has a long, slender body measuring 36–56 cm and weighs 0.5–2.4 kg. Males are significantly larger than females — a typical size dimorphism in mustelids: an adult male weighs 1.3–2.4 kg, while a female weighs 0.5–1.5 kg. Compared to the stone marten, the pine marten is slightly lighter but has a proportionally longer tail (50–55% of body length vs. 45–50% in the stone marten) and a more slender silhouette — an adaptation for life in the treetops.

The fur is dense, double-layered, and soft. The color of the back is a warm, dark brown with a slight chestnut or chocolate tint; the belly is lighter. In summer, the fur is shorter and slightly more reddish, while in winter it is much denser and darker, with a lighter undercoat. Historically, the pine marten was an important fur-bearing species (hence the Polish folk names tumak and golden-throated marten — referring to the color of its bib).

The most important identifying feature is the bib on the chest. In the pine marten, it is cream-yellow to yellow-orange, uniform (without a split), and ends at the chest — it does not extend down the legs or onto the belly. This is a crucial difference from the stone marten, whose bib is pure white, bifurcated (split), and reaches down to the belly. For a full comparison of both species, see the guide pine marten vs stone marten.

The pine marten's paw is densely furred, especially in winter — an adaptation to the cold that facilitates walking on snow and wet bark. The winter fur is so thick that tracks in the snow appear blurred — an important diagnostic indicator in the field. In the stone marten, the paw is only partially furred, so its winter tracks show clearer toe prints.

The pine marten occurs from the Iberian Peninsula to the Urals, as far north as the Kola Peninsula, and south to the Caucasus. In Poland, it is found throughout the country, but with very uneven density. Stable, dense populations are found in the Bieszczady Mountains, the Low Beskids, the Białowieża Forest, the Tuchola Forest, and the larger forest complexes of Pomerania. In forests with short rotation cycles (managed pine monocultures of 30–60 years), its presence is significantly more modest.

The habitat requirements of the pine marten are key to understanding its distribution. The species needs old-growth forest — trees 80+ years old with hollows where it builds nests. Ideal environments include old beech forests, oak forests, mixed fir-beech forests, and spruce forests with rich vertical structure. The more standing and fallen dead wood, the better.

Daytime shelters are critical for the pine marten. It most often chooses: tree hollows (especially abandoned nests of the black woodpecker and grey-headed woodpecker), abandoned squirrel nests (dreys — dome-shaped twig structures high in the canopy), occasionally owl hollows, abandoned birdhouses, and brush piles. A single marten has 5–15 shelters in its territory, moving between them cyclically. It occupies attics of buildings only exceptionally, usually in homesteads bordering forests — this is where it is most often confused with the stone marten.

The individual territory (home range) of a pine marten is significantly larger than that of a stone marten — a male covers 100–700 ha, while a female covers 50–250 ha. This is due to a less food-rich habitat (forests usually have fewer small mammals than agricultural mosaics) and longer distances between good shelters. In winter, territories can be even larger as the marten patrols for carrion left by wolves or in places where game has died.

The pine marten is an opportunistic omnivore with a distinct forest profile. Its diet differs from the stone marten's not so much in composition as in source — instead of the common vole from the fields, it hunts the bank vole in the old-growth forest; instead of the feral pigeon, it targets thrushes and jays; instead of chicken eggs, it takes woodpecker eggs. For a fuller discussion of the food of both martens, see the guide what martens eat.

• Small forest mammals (bank voles, shrews, wood mice, dormice) — 35–50% of the diet for most of the year
• Squirrels — 5–15% of the diet; the pine marten is one of the primary natural predators of the red squirrel in Polish forests
• Forest birds and their eggs (thrushes, tits, jays, woodpeckers) — 15–25%
• Fruit, berries, and nuts (blueberries, rowan berries, blackberries, hazelnuts, wild pears) — 10–25% seasonally
• Carrion (wolf kills, deer carcasses in winter) — an essential element of the winter diet
• Insects, snails, earthworms — a supplement during the summer

Hunting squirrels is one of the most spectacular sights in the Polish forest. The pine marten is one of the very few predators capable of catching a squirrel in the treetops. The chase takes place in three dimensions — up the trunk, through the canopies, in leaps of up to 4 meters. Squirrels can manage smaller predators (hawks, owls), but there is nowhere to hide from a marten. This is why squirrel numbers can be significantly reduced in forests with strong pine marten populations.

The hunting strategy of the pine marten combines two tactics. On the ground, it uses its excellent sense of smell and knowledge of paths to hunt small mammals, much like the stone marten. Arboreally, it patrols the tree canopies in search of sleeping birds, nests with chicks, and squirrels in their dreys. Surplus killing (killing more than can be eaten) happens rarely — unlike martens attacking chicken coops, the pine marten in the forest usually takes individual prey.

Seasonal dietary changes: In winter, small mammals, carrion, and squirrels in nests dominate. In spring — chicks and eggs of forest birds. In summer — insects, young rodents, and berries. In autumn — hazelnuts, rowan berries, berries, and sometimes acorns and beechmast. This dietary plasticity allows the marten to survive in a habitat where there is no single constant food source year-round.

The pine marten is crepuscular and nocturnal, with activity peaks from an hour before dusk until midnight and from 3 AM until sunrise. During the day, it sleeps in a shelter — most often a hollow or a squirrel nest high in the canopy. Unlike the stone marten, which regularly enters farmsteads and is heard there, the pine marten leads a life so secretive that most people living on the edge of its range never see it.

Arboreality is one of this species' greatest evolutionary adaptations. The pine marten spends 60–80% of its time in the tree canopies, descending to the ground only to hunt mammals or travel between groups of trees. It jumps from branch to branch over distances of up to 4 m horizontally and 3 m vertically. It descends trunks head-first (just like a squirrel) using a reversible ankle joint — an adaptation the stone marten does not use nearly as intensively.

Territoriality is strong in both sexes. Male territories may overlap with the ranges of several females — a typical social structure for mustelids. Boundaries are marked with secretions from anal glands, urine, and droppings left on visible objects: stumps, stones, or the roof tiles of forest gazebos. Boundary patrols occur 2–4 times a week, becoming more intense in the spring during the mating season.

Vocalizations of the pine marten are quiet and rare — also a part of its secretive lifestyle. The most commonly heard are: short clicks (mother-young contact), growls (aggression during territorial encounters), and high-pitched squeaks (young calling for the mother). During the mating season, males make a characteristic, dry "clicking" sound — very rarely heard by humans.

The pine marten is quite proficient at swimming. It can cross rivers and streams without difficulty but rarely uses this skill — it prefers to cross on a tree trunk fallen across the water. In the Biała Lądecka river, individuals have been observed swimming 30-meter stretches in cold water.

Reproduction in the pine marten works according to the same mechanism as in the stone marten — with embryonic diapause. Mating takes place in July and August, but the actual development of the embryo only starts in February or March of the following year. This mechanism is delayed implantation: fertilized eggs "wait" in the uterus for 7–8 months in a state of metabolic arrest until day length signals the arrival of spring.

Actual pregnancy lasts 30–35 days from implantation. The young are born in March, April, or May (depending on the region and weather). Litter size is 1–5 young, most often 3 — fewer than the stone marten, but a typical number for K-strategist mustelids (long life, small litter, intensive parenting).

For a fuller discussion of marten reproductive biology, see the article young martens and their development. Here we focus on what is specific to the pine marten.

The female builds the nest in a tree hollow (most often abandoned black woodpecker holes) or in an old squirrel nest. The lining consists of moss, dry grass, and squirrel fur. Location choice is key — the hollow must be high enough (3–10 m) to be out of reach for ground predators and tight enough that another adult male cannot squeeze in.

Development of the young: Eyes open after 5 weeks (later than in the stone marten — due to a warmer, safer nest), first solid food after 8 weeks. First independent excursions from the hollow occur at 10–12 weeks. Independence is reached after 4–5 months. Young females reach sexual maturity at 14–15 months, while males only at 24 months — much later than the least weasel, which breeds after only 3–4 months.

In the wild, pine martens live 8–11 years. This is twice as long as a stone marten in the city (where they mostly die under car wheels) and much longer than a weasel (1–3 years). Main causes of death: predation (rare, mainly from golden eagles and eagle owls attacking the young), hunting, parasitic diseases, and in recent years increasingly — road collisions on routes intersecting forests.

Pine marten tracks in the field are slightly larger than stone marten tracks — a full paw print is 4–5 cm long and 3–3.5 cm wide (vs. 3.5–4 cm in the stone marten). Five toes with claws are visible on fresh, soft ground (wet clay, mud). The gallop pattern — pairs of tracks with 50–80 cm gaps — is typical for mustelids.

A full guide to marten tracks can be found in the article about marten tracks. One specific feature of the pine marten is worth highlighting: winter tracks are clearly blurred by dense paw fur, whereas stone marten tracks maintain clear toe prints even in snow. In summer, the difference fades — then both species leave similar tracks in clay or silt.

Pine marten droppings are small cylinders 6–10 cm long, ~1 cm in diameter, with a twist resembling the letter S — very similar to stone marten droppings. The color is dark brown to black, often containing squirrel or forest rodent fur, berry seeds, and small bones. Fresh ones have a characteristic musky scent. They are left on stumps, stones, and forest bridges as part of territorial marking. They are kept at a safe distance from humans, unlike the stone marten, which might leave droppings on a car hood.

Other signs of presence: picked pine cones in a typical "marten" style (split lengthwise with seeds eaten — distinct from squirrels, which leave cones chewed into a braid), remains of squirrels (fur, tail fragments), dreys with an enlarged opening (a sign that a marten moved into the squirrel's nest), and torn bark fragments on the trunk from sharp claws.

The relationship between humans and the pine marten is much calmer than with the stone marten. The species leads such a secretive life in the forests that most people never encounter it directly in their lives. Conflicts occur mainly in forest-side homesteads — chicken coops, pigeon lofts, and rabbit hutches located at the forest edge may be attacked, though less frequently than by the stone marten. The pine marten also doesn't move en masse into the attics of residential buildings — it leaves that territory to its cousin.

• Damage to forest-edge homesteads — occasional attacks on small livestock; intensity is much lower than with the stone marten.
• Conflict with squirrel and small bird breeding — in small nature reserves and research farms, pressure on squirrels can be noticeable.
• Road collisions — a growing threat on routes intersecting forest complexes (highways, expressways).
• Habitat loss — the most serious long-term threat. Short timber rotation (40–60 years) eliminates hollow trees, which are crucial for reproduction.

Legal status: In Poland, the pine marten is a game species with a closed season from April 1 to August 31 (Regulation on the determination of hunting seasons for game animals) — identical to the stone marten. Hunting outside this period can only be carried out by persons with hunting licenses. In practice, hunting pressure on the pine marten is low: the species is secretive, difficult to hunt, and has no significant fur value (the fur market collapsed in the 1990s). In many EU countries (Germany, Czechia, Slovakia), the pine marten is fully protected — which raises questions about its game status in Poland.

The protection of the pine marten in Poland should primarily involve preserving old-growth forests — leaving hollow trees in forests as so-called "biocenotic trees" (required for several years in forest management), protecting Natura 2000 areas, and limiting forest fragmentation by new roads. Without hollows, there is no marten — it's a simple and irrevocable equation.

Folklore hasn't burdened the pine marten as much as the least weasel. The traditional name tumak originally meant "forest fur animal" and was a respected name — tumak fur was one of the most valuable furs in medieval Poland. Kuna złotodzióbka (golden-throated marten), in turn, refers to the gold-yellow color of the bib. Both names are rarely used today but survived in the names of places.

Despite being harder to encounter than the stone marten, the pine marten has also acquired its share of false labels. Here are the six most common:

• MYTH The pine marten and the stone marten are the same species.

  FACT They are two distinct species — Martes martes and Martes foina. They share the same genus Martes, but differ in their bibs, habitats, lifespans, and reproductive strategies. Full comparison in the guide pine marten vs stone marten.

• MYTH Pine martens attack people in the forest.

  FACT There are no such cases. The pine marten is exceptionally shy — in 99% of encounters, it is the first to flee. It attacks only when cornered, in defense of young, or when diseased (rabies, distemper). An encounter with an active marten during the day should warrant caution.

• MYTH Pine martens cause as much damage on farms as stone martens do.

  FACT Significantly less often. The pine marten prefers the forest and usually finds enough squirrels and birds nearby to avoid coming down to farms. Conflict occurs mainly in forest-edge homesteads, but the scale is 5-10x smaller than with the stone marten.

• MYTH Pine martens are common — you can find them in any forest.

  FACT Only in old forests. Dense populations of pine martens are found in stands 80+ years old with hollows and rich structures. In managed 30-60-year-old monocultures, the species occurs rarely or not at all. It is a forest quality indicator species.

• MYTH Pine martens are still exterminated for their fur.

  FACT The marten fur market collapsed in the 1990s and never recovered. Hunting statistics show that the harvest of martens in Poland is currently very small — mostly by dedicated hunters, not commercial breeding. The game status remains out of habit rather than economic necessity.

• MYTH The pine marten is larger than the stone marten, so it's easy to identify.

  FACT On the contrary — in the field, both species are almost indistinguishable in size. A male pine marten (1.3-2.4 kg) is comparable to a male stone marten (1.1-2.5 kg). The key difference is the bib: uniform cream-yellow = pine, split white = stone.