It's been dubbed the 'Asbo Bambi' and is rapidly establishing local breeding populations across Ireland.
But scientists battling to curb the spread of the dreaded muntjac deer say landowners on the Ards Peninsula are refusing to cooperate – and may not take the threat seriously until there is a serious road accident.
Dr Jaimie Dick at Queen's University Belfast says the tiny, voracious deer is living and breeding under our noses and by the time it becomes noticeable to the general public, it may be too late.
Eleven photographs of muntjac using camera traps have been taken on the Ards Peninsula, where they are particularly concentrated and three carcasses have been recovered but these are just the tip of the iceberg, he said.
Now he is appealing to members of the public to get involved in the battle against the invasive species before it becomes too firmly established to eradicate and begins to causes millions of pounds worth of damage – as has already happened in England.
There, they have established themselves in population densities as high as 120 per square kilometre, they cause millions of pounds of damage to forestry and gardens, they cause road collisions and are dangerous to dogs and people.
They are even responsible for helping drive native plants and birds closer to extinction as they voraciously devour the vegetation.
"We know that they are responsible for significant reductions in nightingale and willow warbler populations in some places," Dr Dick said.
Scientists at QUB warned back in 2008 about the dangers of allowing muntjac to become established – and now their predictions have come true, with the animal now breeding in the wild in Northern Ireland.
Yet some people are still illegally keeping captive breeding stock, Sr Dick said.
"They have come in on fishing vessels, dog trailers, animal trailers, in car boots. I have met one person who kept captive breeding populations in Co Wicklow and sells in Northern Ireland," he said. "I know of at least three locations where they were kept in Northern Ireland, two in the Republic, and that's just the tip of the iceberg. They're kept in cages, bred and sold on to other people.
"They are impossible to confine. The young are about the size of a rabbit and they can get through tiny holes."
But it's now too late to take action against those who keep captive muntjac as the genie is well and truly out of the bottle.
The scientists are now surveying land across the Ards Peninsula, to get an idea of where breeding populations are and eventually carry out culling programmes.
The National Trust has done a good job of eradicating muntjac at Mount Stewart but other landowners on the Ards Peninsula are being less than cooperative about allowing surveys out on their lands, Dr Dick said.
"The more time that goes on, the less chance there is that we can eradicate the muntjac. We need everybody on board," he said.
QUB ecologists Marianne Freeman and Kayleigh Hogg are inviting the public, landowners and wildlife lovers to an information session at the Ards Arts Centre at 7pm tonight and to get involved by visiting www.quercus.ac.uk, the Facebook page at www.facebook.com/NImuntjac, download the iPhone app or email email@example.com.
This tiny non-native deer is the smallest in Britain and has copper-brown fur, with darker markings on the legs and face – which vary depending on gender. They have a hunched posture as their haunches are higher than their front. Males will also have antlers during the autumn although these are straight and short at around 10cm. Bucks also have large canine teeth which protrude and are used in fighting.