Predators
A
ll across Scotland today, predators are out hunting. Many more will join them as dusk falls this
evening. They will slink into burrows, slip into rivers and scramble up trees to raid nests and dens; they will prowl, pounce and kill with skilful precision and remarkable strength.
Yet they move with such stealth that they are rarely seen by their human neighbours, and their presence is often undetected and certainly under- appreciated. But, perhaps, that is about to change. With European lynx the next species on the agenda for possible reintroduction, attention is turning to the place of predators in the Scottish landscape. It’s troubled ground, with strong opinion on all sides; after all, the reintroduction of the strictly vegetarian beaver has hardly been without opposition, so the potential return of an apex predator raises even bigger questions about ecological roles, impacts on other species and, especially, potential conflict with humans.
But while such issues are debated, what can we learn from existing predators about their role in Scotland’s ecosystems, and our attitudes towards them? There have been no large land predators in Scotland for centuries – the last wolf was, reputedly, killed near Findhorn in 1743 – but there are plenty of smaller ones, which brings us back to a fierce family: the Mustelidae. More commonly known as the ‘weasel family’, its members are characterised by long bodies, short legs, strong jaws and sharp teeth.
In Scotland, mustelids are represented by a gang of seven. It includes the largest British land carnivore, the badger, and
the smallest, the weasel; one of the rarest mammals in the country, the polecat, and one of the most abundant, the stoat; two conservation success stories, the otter and pine marten; and one unwanted visitor – the American mink. While many mustelids are omnivorous, with insects, fruit and berries featuring prominently on their seasonal menu, they are also predators – often with an impressive ability to take and carry away prey that is many times larger than themselves. This capacity to kill has historically put mustelids in conflict with people, especially poultry farmers and gamekeepers. The attitude encapsulated in literature, such as when Kenneth Graham’s Toad Hall was beset by gangs of “skirmishing stoats and bloodthirsty weasels”, is a perception that has often informed attitudes towards them. Stoats were the target of intense predator control in the 19th Century, although they successfully dodged population decline by moving and reproducing fast. Pine martens and polecats, however, were persecuted to near extinction.
GAINING LOST GROUND Protective legislation since the 1980s and ongoing habitat restoration have led to the recovery of pine martens across much
Pine martens and polecats were persecuted to near extinction.
of their former territory – with benefits for another key Scottish species. Before Emma Sheehy became a Conservation Officer for the Trust-led Saving Scotland’s Red Squirrels project, she studied pine marten interaction with squirrels in both Scotland and Ireland. Her research demonstrated that the presence of pine martens heavily suppresses grey squirrel populations to such an extent that it reverses the usual competition dynamics between squirrels. “Reds do better than greys where pine martens are present, in any habitat,” Emma explains.
As pine martens and red squirrels have lived alongside each other for millennia, red squirrels evolved an innate caution around their agile foes. Grey squirrels have only ‘met’ pine martens relatively recently in evolutionary terms, and seem oblivious to the threat and are therefore vulnerable. “Predators get a bad rap, from the first fairytales you hear as a child to headlines in the papers today,” believes Emma. “The mink is a good example of a non-native predator that’s had a hugely negative impact on native species, and this feeds into the narrative around predators. “But what we’ve seen with the pine marten is a native predator recover and help to combat an invasive species. It shows the return of native predators can bring benefits – and raises questions about what other damage has been done that could have been prevented if it had not been for the paucity of natural predators.” So, pine martens are good news for red squirrels, but of course ecology is always more complex than just ‘goodies and baddies’. There are environmental concerns about
Weasel
Stoat
Polecat NOVEMBER 2020 SCOTTISH WILDLIFE 25
© Elliot Smith
© Margaret Holland
© John Bridges
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