HAVE you ever heard someone say, ‘I think I saw a weasel’? If that person was in West Cork, or anywhere in Ireland, they would technically be mistaken.
Weasels are members of the mustelid family, but Ireland has fewer native mustelid species (four) than neighbouring Britain (six), and weasels (Mustela nivalis) are notably absent.
Instead, Ireland is home to the wonderful Irish stoat (Mustela erminea hibernica), which, along with our other native mustelids, badgers, otters, and pine martens, more than makes up for the absence of weasels.
Marvellous mustelids
Mustelids are carnivorous mammals with long, slender bodies, which allow them to pursue prey such as mice, voles, and shrews into small tunnels and burrows.
The family name, mustelid, comes from the Latin mustela, meaning weasel, which is perhaps where the use of the catch-all term ‘weasel’ for small mustelids arose.
Unlike animals such as birds, butterflies, or even foxes, mustelids tend to be cryptic and elusive, rarely seen in the wild.
If you are lucky enough to catch a glimpse of one, it is usually fleeting.
All native mustelids in Ireland are protected under national and international legislation.
Under the Irish Wildlife Act, it is an offence to capture or kill a pine marten or Irish stoat or to destroy or disturb their resting place.
Stoatally wonderful
The Irish stoat is the smallest mustelid in Ireland, measuring less than 40 cm in length, excluding the tail.
It is also one of Ireland’s oldest mammals, with fossilised bones between 27,000-35,000 years old found in a cave right here in Cork.
This unique subspecies of stoat is found only in Ireland and on the Isle of Man.
The Irish stoat has striking chestnut-brown fur with a cream-coloured underside. Its long tail has a distinctive black tip.
It occupies a wide range of habitats, from woodlands and hedgerows to dry-stone walls.
Despite its small size, it is an impressive hunter, capable of taking down prey several times its own weight, including rabbits.
Due to their secretive nature, little is known about the distribution of the Irish stoat in Ireland.
To address this, the Vincent Wildlife Trust launched the first-ever citizen science survey for stoats, which concluded last month.
Keep an eye out for the upcoming report at vincentwildlife.ie.
An enemy of the enemy
One of Ireland’s most remarkable native species recovery success stories is that of the pine marten.
In the mid 20th century, the species was on the brink of extinction.
Their decline was primarily due to removal of their woodland habitat, poisoning, and persecution.
However, legal protection, natural recolonisation, and improved forestry practices have helped their numbers recover slowly.
This recovery has had a positive knock-on effect on ecosystem balance. Invasive grey squirrels are known to outcompete and reduce red squirrel populations, but in areas where all three species coexist, the presence of pine martens has been shown to suppress grey squirrel numbers, allowing red squirrels to recover. Unlike their non-native counterparts, red squirrels have evolved alongside these native predators. Since grey squirrels damage woodlands by stripping bark and threaten red squirrel populations, pine martens are often considered an ally in conservation efforts; an enemy of the enemy.
Cat crainn
Pine martens are visually striking, with chestnut-brown fur, a creamy yellow or orange chest patch, a white throat, and large, rounded ears fringed with pale fur.
Their long, bushy tails add to their distinctive appearance.
They are mainly active at dusk and dawn.
In the past five years, there have only been a handful of sightings across West Cork, but intermittent reports are an encouraging sign.
Glengarriff is a known location for pine martens, which makes sense given their preference for woodland habitats.
Their excellent tree climbing skills are reflected in their Irish name, cat crainn, meaning tree cat.
While their numbers have increased, pine martens are still far from reaching their original population levels.
They continue to face threats, and recent studies show due to their near-extinction and subsequent recovery from a small gene pool, they have low genetic diversity, making them less resilient.
They are not out of the woods yet, but conservationists are keeping a close eye on them, and there is reason for optimism.
The elusive Irish stoat is one of the country’s oldest mammals. (Photo: Cate O'Sullivan)
Invasive mink
One member of the mustelid family is far less cherished than the rest, the American mink.
As the name suggests, mink are native to North America and are an invasive species in Ireland.
They have a significant negative impact on Ireland’s freshwater ecosystems and wildlife, particularly water birds.
Ground-nesting species are especially vulnerable, as mink prey on eggs, chicks, and even adult birds.
Mink are usually dark brown, sometimes appearing black, with occasional white patches on their chin or underside.
They are often mistaken for otters, but they are significantly smaller, move differently, and have a thinner, shorter tail.
Fur farming legacy
Mink were first reported in Ireland in 1961 after escaping from a fur farm in Northern Ireland.
They breed prolifically and, with no natural predators, their numbers quickly grew following subsequent fur farm escapes and releases across the island.
Targeted control efforts take place at protected sites such as Wexford Wildfowl Reserve and the Breeding Waders European Innovation Partnership Project at the Shannon Callows.
Polecats are a native mustelid in the UK, while ferrets are a domesticated form of this species. Neither are native to Ireland, but there is a relatively small yet widespread population of invasive ferrets, likely escapees from captivity
You are very likely to spot mink in West Cork, but far less likely to see pine martens or Irish stoats.
However, these elusive native species are present in small numbers, so keep your eyes peeled!
