Over the years, I’ve had some late-night near misses with deer on rural roads, but nothing as surprising as a recent daytime encounter with Sika deer within a stone’s throw of the M50 in Dublin. Four of them were eating a patch of verdant, thick grass, and as I approached, they barely flinched. One threw me a quick doe-eyed glance, perhaps making sure I wasn’t a hunter with the butt of a rifle against my shoulder, but the others continued to graze, unfazed.
Deer are nearly everywhere, the result of a pandemic-fuelled explosion in numbers when hunting and culling were restricted, and the wild venison market collapsed due to restaurant closures. Deer are tricky to count – there has never been an Irish census – but the legacy of those few years can be seen in the colossal damage to woodlands and farmland and the expansion of their range across the country.
A few weeks ago, I joined forester Paddy Purser in a mixed woodland in Wicklow. The damage inflicted by invasive deer is so distinct that it has its own lingo. Purser showed me an example of bark stripping, where deer rip the bark off with their teeth. This vertical gash, an open wound, leaves the tree vulnerable to disease. Male deer remove their velvet-like skin from their growing antlers by “fraying” and rubbing their heads against the trunks of saplings, which can cause the trees to die. Purser pointed out numerous examples of “browsing” on the woodland floor, where hungry deer had stripped plants back to their bare stalks.
The result of excessive deer numbers is a grim, hollowed-out woodland devoid of young trees, plants and other vegetation, which leaves little to nothing for ground-nesting birds, insects and other life. Without this rich understory, the wood has little hope of regenerating. There are no sustainable native woodlands in Wicklow, Purser told me, adding that unless invasive deer numbers are appropriately managed, the impacts would be “catastrophic” within 10 years.
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The government wants to “urgently” and “substantially” expand tree planting from today’s 11.6 per cent forest cover to 18 per cent by 2050 as part of its climate and nature targets. For deer, the prospect of millions of young trees in the ground is akin to leaving out bread for the pigeons. The current solutions – millions of plastic tree guards, hundreds of kilometres of deer fencing, replacement trees and labour – are excessively expensive.
Each year 350,000 are culled, but an estimated target of up to 750,000 is needed to stabilise the population
Of the species here, only the small Killarney red deer population can claim to be a unique population that can be traced back more than 5,000 years. Thousands of red deer were imported during the 1980s and 1990s for farming; fallow deer were introduced during the 1200s; sika deer were brought here in 1860; Reeve’s muntjac deer appeared in the early 2000s, and in the past few years there have been sightings of Roe deer and unconfirmed reports of Chinese water deer.
Deer are now so numerous that they’re clearing farmers out of grass and over-grazing fields in the summer months, which puts pressure on winter feed. In Tinahely, farmer John Mallick, whose fields border Coillte woods where deer thrive, told me that groups of deer regularly grazed the grass he grows for his livestock. On an adjoining road, he pointed out deer tracks and the damage done to ditches. There’s no controlling their movements, he said, clearly fed up with the escalating problem.
Controlling numbers is a huge undertaking. In the UK, where deer cause 74,000 traffic accidents yearly, the population has doubled since 1999 to two million. Each year 350,000 are culled, but an estimated target of up to 750,000 is needed to stabilise the population. And so, the herds will continue to grow.
Invasive deer in Ireland have no natural predators (the last grey wolf was killed about 238 years ago), so the only pressure on them is from humans with guns. Deer are still legally protected, and can only be shot under licence; in the past five years, a quarter of a million of them have been killed at no cost to the State. Hunting licences have increased by 45 per cent in the previous 10 years, but there’s a mismatch between recreational hunters, who often prefer to target trophy males with antlers – something that will do little to control numbers – and the need to prioritise females.
What’s a sustainable number of deer in Ireland? Research from Scotland indicates that a density of 3.5 deer per square kilometre is low enough to allow the successful regeneration of young Scots pine trees. In some parts of Ireland, deer density is estimated to be as high as 40 animals per square kilometre. The Government has allocated €3.4 million of public money to set up local units, but deer experts told me it would cost that amount to deal effectively with the problem in Wicklow alone.
In the long term, wild predators might do a more effective job. The Labrador-sized Eurasian lynx, a long-legged reclusive wild cat that poses no physical threat to humans and has been reintroduced across Europe, specialises in taking small deer and could do well hunting muntjac and young sika (it also takes rabbits, foxes and birds). Research led by Colin Guilfoyle at the Atlantic Technological University indicates there isn’t enough habitat for lynx to survive here, but under a future 18 per cent forest cover, that’s likely to change. However, while lynx are reclusive creatures of trees, they’re capable of adapting to the local landscape and will kill sheep, so their introduction is unlikely, at least in the short term.
Attempts to effectively manage the wild population in Ireland have failed. Numbers are at a historic high in the UK; it’s probably the same here. The gaps in the data – How many deer are there? What are the evidence-based targets? – need to be filled. The most important stakeholders aren’t just the farmers, landowners and hunters; it’s all of us. We will not reach our nature restoration goals without urgent action. The cost of failure is high.