Harmless or Horror: The truth about the Pine Marten

Caroline McKeon on Ireland’s rarest mammal 

If you listen to the media, a lot of things these days are pure evil.

Wind farms, coal mining, animal protein, Donald Trump, vegans, you name it. While some of these Demons undoubtedly deserve their reputation, others are getting way too much abuse. In an effort to right some wrongs to a poor arboreal mustelid’s reputation, let’s shed some light on the pine marten.

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You might have heard some things about these elusive creatures recently. You might have heard they are protected under Irish and EU law, or that they have semi-retractable claws like a cheetah. You may also have heard that they drink the blood of sheep at night, and soon they will be attacking human babies, “[as they have done in England]”. Fortunately, only the first two rumors are true. Unfortunately, the rest are still being spread.

There is a current political climate of locally manufacturing “truth”, no outsourcing to the distant realms of fact or reality required. If it can teach us anything, it’s that unfounded scaremongering and misinformation can do a lot of harm to vulnerable, important things, like trust, EU membership and pine martens.

With that in mind, let’s get out some legitimate mustelid knowledge.

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As mentioned, pine martens (Martes martes) are part of the mustelid family, along with otters, weasel, badgers, stoats etc. At under half a meter long, their aptitude for climbing and secretive nature earned them the Irish name cat crainn – literally meaning tree cat.

A native to Ireland since the end of the last glaciation circa 10,000 years ago, these habitat specialists prefer mature broad-leaf or mixed deciduous woodland.

Pine martens are found all over Europe, from western Russia to Italy. In the northern mainland they co-exist with stone martens, and towards Eastern Europe, with the sable marten, which may start to sound familiar as you think about gloves and thick, expensive coats.

Martens in their native habitat; Milan


Why they are rare

Though they have Least Concern conservation status in Europe, pine martens went through some dark times in Ireland and the UK. The fur trade that once drove Russian commerce and fueled European exploration across the top of northern America had a strong lust for pine marten. The value of their hides was such that the exports came to be known as soft gold. By the early 1900’s, a combination of deforestation, predator persecution and direct hunting for furs drove populations of Ireland and the UK to dangerous all-time lows.

Only strongholds in the wild Irish west, Scottish highlands and tiny pockets of Wales remained; the marten was locally extinct in England.

In a testament to how scarce and how extremely elusive they are, a forty year man-hunt went by in Wales without one sighting of a pine marten. The evidence before and after was roadkill.

A young marten        Image Source

In an effort to restore populations, pine martens were given protection under Irish law in the 1976 wildlife act (renewed in the amendment in 2000). They are also protected under the EU habitats directive (1992) among other legislation.

Since their protection began, combined with the slow afforestation of Ireland, they have been recovering. However, the estimated 2,700 Irish martens currently occupy half of their original range, and are under researched.

A pine marten savaging a juvenile human Image Source

Now for the controversy; they face some serious opposition.

“We are seeing species that have never been seen before in Ireland being introduced by these people. Look at the pine marten, the most nasty vicious bird that you have ever seen. They were never in Ireland but have been introduced.”

In keeping with the aforementioned political climate of hilarious but damaging lies…

Pine Marten (Martes martes), zoo, Arth Goldau, Switzerland
DKFJN3 Pine Marten (Martes martes), zoo, Arth Goldau, Switzerland                 (NOT A BIRD)


Bizarre inaccuracies aside, there is a real issue at the moment. Sheep farmers in the midlands continuously claim that pine martens have been steadily killing their lambs, that they vampirize sheep, and that they have attacked babies in England. Calls for culls, and lifted bans and shooting licences ensue.

This is where I feel like a vigilante fighting unscrupulous criminals, hampered by my own unwillingness to take a life – or in this case, make unsubstantiated claims.

We have no proof that a pine marten has never killed a lamb. That would mean witnessing the entire life of every lamb ever born, to validate that its death could not be attributed to the mustelid. However, we also have absolutely no proof that pine martens do kill lambs, and plenty of reason to believe that they don’t.

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1)      Size. 45-50cm body length, with males weighing 1.5kg on average. Well over 10 times lighter than their alleged prey.

2)      Feeding habits. Most convincing after the blatant size discrepancy and lack of hard evidence, is the martens well studied dietary range, established through both scat and stomach content analysis.

The proof is in the poo.

Marten scat clearly rich with Autumn berries                                                 From the VWT twitter

Pine martens are omnivore generalists, eating a wide range of food depending what is available seasonally, and also in their locality. Diet includes small mammals, birds, eggs, amphibians, invertebrates, fruit, mushrooms and carrion. Studies show that when all options are on offer, cat crainn prefer microtinae like voles, Norway lemmings, or the unrelated but equally delicious shrew. In autumn fruit and berries become more important, as do beetles and other insects in summer. One Scottish marten’s stomach contents even contained fish! Carrion becomes more important during the winter, especially in the harsher northern areas. Analysis reveals pine martens to have consumed the meat of large herbivores like elk and reindeer. AH! You say. I knew it! So they’ve been killing the livestock in Ikea too! Well hang on, no.

Given their known habit of eating available carrion, isn’t is more likely that martens have been scavenging from recently dead lambs than actively killing them?

Let’s round up with some of the reasons to keep them on the rise.

Non-native pest control? It’s kind of a grey area.

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“Like most predators, [pine martens] turnout to be essential to the survival of a healthy living systems” –George Monbiot.

Grey squirrels, an invasive American species have been a) pests and more importantly b) decimating our native red squirrel population unchecked through competition and as vectors of disease.

Have been.

Though the mechanism behind any causation has not been proven, there is a powerful correlation between areas of pine marten recolonization, grey squirrel population crashes and red squirrel resurgence.

Grey squirrel population has crashed in a 9,000km2 area of the midlands, red squirrels are now common after 30 year absences, as they experience competitive release. Pine martens are suggested as “critical factor” the grey’s definitive decline.

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Red squirrels co-evolved with these mustelids, and are swift and light, feeding high in the trees and escaping down thin branches out of reach. Martens hunt on the ground, where the grey preferentially forage. It is suggested by poor condition of remaining greys in marten recolonised areas, that the native mustelid is creating a landscape of fear. As they spend time on look out and vigilance behaviour, grey squirrels may not be able to put on the weight they need to make it through the winter and so are starved out.

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Why support the pine marten? Classic flagship species. Top predator of the forest understory, restoring balance to rats, rabbits and all sorts of mice. Key link in the ecosystem’s food web – seeming to demonstrate the proverbial resilience of health ecosystem’s to non-native invasives. Charismatic, furry carnivore, evolved with unique adaptations for capturing the imaginations much of the general public’s naturally disinterested ranks. And most of all, we need to take special care of our biodiversity, because of islands’ vulnerability to extinction. Something funny to tie it up, the end.




De Marinis AM, Messeti M (1995) Feeding habits of the pine marten Martes martes in Europe: a review. Hystrix 7:143–150 martens are generalist feeders, varying diet according to what is available.

Sheehy, Emma and Colin Lawton. “Population Crash In An Invasive Species Following The Recovery Of A Native Predator: The Case Of The American Grey Squirrel And The European Pine Marten In Ireland”. Biodiversity and Conservation 23.3 (2014): 753-774. Web. 5 Sept. 2016.


Pine marten




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