The otter pops back into view...but ducks won't take to cleaner water
Otters are making a comeback to our lakes and rivers following decades of decline – and it's down to rising water quality.
Environment Minister Mark H Durkan revealed that numbers have increased by more than 25% in under a decade, a remarkable turnaround in fortunes for a secretive mammal that has vanished from many parts of the UK.
The most recent survey showed that otters are now present at 334 of the 377 sites examined – an increase of 26.9% since the last survey.
It's not only good news that otters are returning, but it's a sign that the invasive American minks are being pushed out as the two rarely co-exist, according to Ulster Wildlife nature reserves manager Andy Crory.
The mink is on the top 10 most unwanted invasive species list and wreaks havoc on riverside habitats, devouring small mammals and birds.
"When the otters move back in they're doing the other wildlife a big favour – they will force the mink out or even kill it," he said.
"It's a native species reclaiming its habitat from the invader. It's not just a nice thing to have back, but it probably means the river is a healthier place."
Otters were once persecuted by humans, hunted by specialised dogs called otter hounds. Populations were also devastated by poor water quality which wiped out the fish they needed to survive.
Six Special Areas of Conservation have been named in Northern Ireland to protect otters, which are a European Protected Species.
Otters are good indicators of water quality – they need clean, unpolluted water with a large and varied supply of food. Dense, undisturbed areas of bankside vegetation are also essential to provide cover during the day and for breeding purposes. Otters are active all-year round and are mainly nocturnal. They often leave droppings to mark their territory.
Ducks won't take to cleaner water
More than 100,000 diving ducks used to overwinter on Lough Neagh as recently as the turn of the century.
Then came the crash, and scientists were mystified as populations plummeted by as much as 60% in less than a decade.
Now they have come up with what they think may be one of the reasons those huge flocks of pochard, tufted duck and goldeneye have vanished from the UK's biggest freshwater lake – and it could be down to cleaner water.
Dr James Robinson, NI director of the RSPB, which has teamed up with Queen's University Belfast and the Northern Ireland Environment Agency to investigate the mystery, says the overwintering birds appear to be losing much of their food supply.
Between winter 2001/2 and 2008/9, the overall diving duck population dropped by 63%.
New research published by a Queen's University team suggests that the midge larvae the ducks rely on to survive through the winter massively declined in numbers during the same period as the duck population crash.
"It could be connected to improvements in water quality," said Dr Robinson.
"It may be that something that is trying to improve the environment is resulting in the loss of these birds."