Research
O’Reilly, C. et al. (2021) Not out of the woods yet: genetic insights related to the recovery of the pine marten (Martes martes) in Ireland
Species Pine marten
Facts about pine martens
- English/Irish name: Pine marten/Cat crainn
- Scientific name: Martes martes
- Number of young: Between 2-3, called kits, born March to April
- Diet: Small mammals, berries and fruits, invertebrates, birds and amphibians
- Habitat: Requires woodland or scrub habitat that provides cover and protection from predators such as foxes
Identification
Females:
length 46-54cm; tail length 18-24cm; weight 1.5kg; life span 7-10 years in the wildMales:
length 51-54cm; tail length 26-27cm; weight 2kg; life span 7-10 years in the wild- Pine martens have dark brown fur with a creamy yellow throat patch — known as its 'bib'.
- The pine marten has a tail that is long and bushy.
- Pine martens are about the size of a domestic cat.
Photos: ©Ruth Hanniffy
History of pine martens in Ireland
Pine martens have been present in Ireland for at least 2,800 years. At that time, Ireland had significant woodland cover. How pine martens arrived in Ireland remains uncertain, but genetic studies suggest a link to populations from Iberia and southern Europe. This, along with the absence of pre-human fossil evidence, indicates that pine martens were likely introduced by humans, possibly for their fur or as a food source.
During medieval times, pine martens were highly valued for their pelts. Overhunting and widespread deforestation led to a severe decline in their numbers. By the 1980s, the species was on the verge of extinction, surviving mainly in the woodlands west of the River Shannon, with smaller populations in the Slieve Bloom Mountains and isolated areas of Meath and Waterford.
The introduction of legal protection under the Wildlife Act 1976 in the Republic of Ireland, followed by the Wildlife (NI) Order 1985 in Northern Ireland, marked a turning point for the species. The ban on strychnine poisoning in the 1990s and increased forestry provided a more suitable environment for their return. Today, pine martens are present in every county in Ireland.
Despite their remarkable recovery, the Irish pine marten population still faces genetic challenges due to historical genetic bottlenecks, which occurs when a population is severely reduced in size, often due to environmental events (like natural disasters) or human activities (like hunting or habitat destruction). Studies of pine martens in Ireland indicate a low genetic diversity, which could affect their long-term viability.
Distribution and status
Today, pine martens are present in every county in Ireland, with higher concentrations in western counties and the Midlands. They remain scarce throughout most of Munster and Ulster. Their conservation status is considered favourable, with the IUCN listing them as a species of Least Concern.
The pine marten is about the size of a domestic cat, with a slender, elongated body and a long bushy tail. Its fur is chestnut to dark brown in colour, with a distinctive creamy-yellow bib on the throat that extends to the chest. It has prominent, rounded ears that have a pale outline.
Seasonal and unique coats
In winter, the pine marten's fur becomes thick and fluffy to provide warmth, while in summer it grows shorter and darker to suit the warmer weather. Each pine marten has a unique bib pattern, much like human fingerprints, which can be used to identify individuals.
Pine martens prefer deciduous woodlands as their main habitat — but if this is not available, they adapt to various environments that offer shelter and food, including commercially managed coniferous plantations, scrub, rocky areas, and crags.
Pine martens typically rest and breed above ground in tree cavities that are high enough to keep them safe from predators, such as foxes, and big enough for an adult female and her kits. Many of the trees in Ireland are not old enough to have such cavities, so they use alternative sites such as rock crevices, burrows, buildings, nests, squirrel dreys, and log piles. In some areas, VWT is working with other conservation organisations to install pine marten den boxes on trees as secure alternative to tree cavities.
As territorial animals, pine martens maintain territories ranging from 50 to 400 hectares, with some overlap between neighbouring individuals. (For reference, one hectare is roughly the size of an international rugby pitch.)
Pine martens are a medium-sized mesocarnivore whose diet consists of 30-70% meat with the rest consisting of fruits, nuts, eggs, invertebrates and fungi.
Despite being classified as carnivores, pine martens are adaptable and opportunistic, which means that they change what they eat depending on the season and what is locally abundant. In the trees and bushes, they may eat squirrels, birds, insects, fruit and nuts. On the forest floors and in the scrub and grasslands, they will eat small rodents, amphibians, reptiles, invertebrates, fungi and even carrion (dead animals). In some areas where pine martens occur close to towns and villages, the species will raid rubbish bins for food.
Pine martens are slow breeders. They don’t reproduce until they are two or three years old, only breed once a year, and usually only have one to three kits in a litter.
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 in early spring when the weather is warmer, and food is more abundant.
At birth, each kit weighs around 30g. Their eyes are closed, and they have a fine covering of silver hair. A safe den that is elevated, warm, and cosy is crucial to the kits’ survival. They will stay in the den for about six or seven weeks and depend on their mother.
Once the kits are about seven weeks old, they explore outside their den. They 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.
The introduction of legal protection under the Wildlife Act 1976 in the Republic of Ireland, followed by the Wildlife (NI) Order 1985 in Northern Ireland, marked a turning point for the species.
There are still, however, a number of factors that can have an impact on pine marten populations, including forest management practices such as harvesting, habitat fragmentation, illegal persecution, and destruction of forest/scrub habitat for development.
Active Projects
Working with Councils and communities to ensure pine martens can continue to thrive across Ireland
FAQs about pine martens
Pine martens are related to badgers, otters and polecats, all of which are members of the weasel family or Family Mustelidae.
Mustelids are small to medium-sized carnivores, and most have long slender bodies, short limbs and long tails. The pine marten is a tree-dwelling mustelid, similar in size to a domestic cat, and has sharp, well-developed claws for climbing trees and a long tail to help it balance as it travels along branches.
Pine martens and red squirrels have evolved together throughout their Eurasian range in a natural predator/prey relationship, though studies in Britain and Ireland show a low occurrence of red squirrel in the diet of pine martens.
Research in Ireland and Scotland has shown that where pine martens are naturally recovering their former range and have established good breeding populations, grey squirrel numbers are decreasing, allowing recolonisation of woodlands by red squirrels (see paper here and here). Scientists are not sure why or how this happens and further research is needed to fully understand the dynamics between the three species.
Although pine martens mainly predate on small mammals such as voles, birds form a part of their varied diet, and so wild birds and game birds (reared for shooting) may also be predated.
Before being hunted and trapped to near extinction, pine martens evolved and co-existed with all our native birds in the wild for thousands of years, and they play an important role in the food chain. Pine martens naturally occur in relatively low densities in the landscape and will take advantage of food sources that are locally abundant; they are therefore most likely to predate on bird species that are common and less likely to have an impact on rare birds. They are opportunistic and will predate on birds’ eggs if they come across a nest, something that many other native carnivores and bird species also do.
As pine martens eat what is most commonly and abundantly available, they are unlikely to significantly impact bats or hazel dormice. There is little evidence that pine martens regularly predate on bats, although there is a possibility that pine martens may use the same buildings to den in that bats also roost in.
As with pine martens, hazel dormice typically exist in low population densities in woodland. Hazel dormouse nest boxes have small entrance holes facing towards the tree trunk and lids are typically secured in place, to protect them from predators.
Pine martens are naturally curious animals and do visit gardens in search of an easy meal, such as food left out for family pets and wildlife, food stored in sheds or discarded in rubbish bins. They will, however, move away if no food is readily available.
To help make sure that any small pets (such as rabbits and guinea pigs) and hens are safe from pine martens, make sure that their housing is secure with no holes greater than 45mm that a marten may fit through. Pine-Marten-Leaflet.pdf (vwt.org.uk). If you have a pine marten visiting your garden, please let us know here.
If you see a pine marten in Ireland, please report your sighting here.
Further reading
Guidance document
A guide to identifying the small mustelids of Ireland
Scientific report
All-Ireland Squirrel and Pine Marten Survey 2019
Website
Pinemartens.ie
