A boy I knew in England kept a ferret down his jumper (but not in school). He wouldn’t let me hold it because, not knowing me, it “might set up a pong”. The ferret’s full scientific name, Mustela putorius furo, can indeed translate as “stinky raging thief” but it also makes a silky, tactile, intelligent pet – “charming and cheeky” in the benevolent view of Britain’s RSPCA.
In the wild, however, it’s an efficient killer of rabbits, rats, hares, hedgehogs and birds. In the wrong place, it can be an invasive menace to wildlife. On Rathlin Island, off Co Antrim, some €5.3 million will be spent over the next five years to exterminate the ferrets and, afterwards, the remaining brown rats. Both are predators on the eggs of the ground-nesting lapwing and corncrake and the island’s puffins and other protected seabirds.
Ferrets are domesticated polecats, never native to Ireland. Identified from road deaths in the late 1980s, in Co Monaghan and elsewhere, they were judged to have established feral colonies in Ireland.
This can’t have been any great surprise, given the past and common use of imported ferrets in the trapping of rabbits for food in rural Ireland and also as a common Sunday “sport”. The later introduction of ferrets to Rathlin, intended as a curb on the island’s rabbits, was an understandable mistake.
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With the arrival of myxomatosis, ferrets were no longer used to scare rabbits into nets. As redundant hunters, or as escapes from former fur farms around the Border counties (now banned), ferrets are breeding widely in the wild.
An all-Ireland citizen science survey from 2006 to 2008, led by Dr Daniel Buckley, produced a map of sightings for Biodiversity Ireland. They came from 19 of the 32 counties, stretching along the east and south from Rathlin to West Kerry, with a heavy cluster in the Border counties. Most were of the dark-furred polecat-ferret, but there were also the frequent albino morph of my drawing, pale, red-eyed, known as the “greyhound” kind and still often preferred as pets.
The planned baiting, trapping and culling of ferrets on Rathlin, due to begin at the end of autumn 2023, is generously funded as an EU Life project and directed by Dr David Tosh, a conservation biologist with the Royal Society for the Protection of Birds (RSPB). It has the backing of the island’s 150 inhabitants, as Rathlin Acting for Tomorrow (Life Raft). There will be help from Wildlife Management, an Irish company more used for problems of urban seagulls and garden foxes.
In the Life programme’s account of Rathlin’s project, predation by rats and ferrets is linked to declines of seabirds, the loss of Manx shearwaters and choughs.
A study of the ferrets’ diet found rabbits contributing about 75 per cent, with birds, carrion and brown rats important in the rest. Shell fragments in the animals’ scats suggest that “birds eggs are likely to be an unrecorded component of the diet”.
Many of the nesting seabirds are on cliffs quite inaccessible to ferrets, but puffins nest in holes beneath the cliff-top turf and plants. Thermal cameras set on cliff-tops at night have already pointed to the greater role of rats in the plunder of their eggs.
Camera traps will be used to help map the ferrets’ whereabouts at different times of year and find the best places for catching them. The roaming patterns of the island’s domestic cats will also be radio-tracked to minimise trapping overlap and misadventure.
As if the ferrets’ natural span of predation wasn’t culpable enough, those introduced to New Zealand are considered important spreaders of bovine TB.
In other times, the animal had a different place in Ireland’s rural culture. As Michael Conry relates in his book The Rabbit Industry in Ireland, the use of ferrets to panic rabbits from their warrens into nets was a profitable venture, especially for export to the UK in the second World War.
A ferret imported from England, as Conry describes, cost 30 shillings. It needed muzzling when put down the rabbit burrow or it could stay below to finish gnawing on its prey and go to sleep. Bonding to its owner and hissing at strangers, it could be kept in a coat pocket to warm a hand on a cold day or let play with the dog on the kitchen floor. The milk a ferret left behind in its dish was a great cure for whooping cough, as everybody knew, and people would come miles to beg for “the ferret’s leavings”.
In his book on the smaller mustelids, Stoats and Weasels, Polecats and Martens (1989), Dr Paddy Sleeman noted that ferrets “are used in civil engineering to thread wires such as telephone wires through long pipes: they are just the right shape and size for the job”. Might they also speed up the connections of cable broadband?