Blackwater home for elusive otters

A STRANGE thing about otters is that, even though they can be found around many rivers and lakes, you don’t see them that often.

Shy, elusive creatures — up to a metre long to the tip of the tail with a thick, brown coat of fur — they generally emerge at dusk, or after dark.

There was a dramatic decline in the otter population throughout Europe in the second half of the 20th century, but the falloff here has been much less and the national otter population is now around 12,000, according to the National Parks and Wildlife Service.

Work is being undertaken on three rivers in north Cork to help halt the decline in the European otter population. Ireland has long been considered a stronghold of this mammal, but it is not as widespread here as formerly.

Like many other animals in the wild, the otter has been hit by loss of habitat and the latest project aims to improve habitats of the otter and other species in the catchments of the rivers Allow, Dalua and Brogeen, with work continuing until 2014.

It is part of a €1 million EU LIFE + funded project being carried out by the regional development company, IRD Duhallow, with Inland Fisheries Ireland. The rivers are important tributaries of the Munster Blackwater which is listed as a designated conservation site for species, including otter.

Encouragingly, the findings of a three month-study conducted as part of the project found evidence of otter activity in most of the sites surveyed. A total of 51 sites in designated special areas of conservation along the three main rivers were probed.

The primary aim was to identify areas in the Allow catchment where otter activity is low to direct habitat improvement works.

A first report on the project, which outlines the areas where otters are known to exist, has now been completed and is about to be submitted to the European Commission.

Pat Fitzpatrick, project co-ordinator, said evidence of otter occurrence was highest on the Allow at 60% of sites compared with only 10% on the Brogeen. Data collected on the distribution and the occurrence of otters has been entered into a database together with other relevant habitat statistics.

An important element of the project is the placement of otter holts, or specially constructed breeding boxes, in areas where otter occurrence is low.

Nationally, a study in 1980/81 showed otters were present in 88% of surveyed sites. Ten years later, this had dropped to 75% of sites, while a survey in 2005 reflected a further drop to 70%.

The otter is one of Ireland’s oldest mammals with records of habitation stretching back to the end of the last ice age, about 10,500 years ago. It is extremely well adapted to water and is an excellent swimmer. Otters mainly feed on fish, including salmon, trout, eels and crayfish, but also small mammals, frogs, dead animals or water birds.

Their large lungs allow them to stay under water for several minutes, although most dives last for one minute. They swim low in the water, with only their eyes, ears and nose above the surface.

As is generally the case, an abundant presence of wildlife is a sign of clean water. The otter, however, has become victim to water pollution, habitat destruction, road kills and fish traps.

Drainage works, interference with riverbanks and vegetation clearance have all taken their toll on otter habitat in Ireland.

Fully protected under the Wildlife Act 1976, it is an offence to hunt, disturb or intentionally kill an otter. The animal is also protected under EU law and the habitats directive obliges member states to designate special areas of conservation, of which there are 44 in Ireland, including river channels, coastline, offshore islands, lakes and bogs.

The otter is a territorial animal that will guard its territory from intrusion by other otters. If you cannot see an otter, there are telltale signs that indicate its presence. A spread of its droppings marks out an otter’s territory and this evidence can be found on large rocks, bridges, or on grassy knolls along riverbanks.

Well-worn pathways leading to water give further clues, while astute observers also look for footprints, especially those with webbing between the toes. People also search for above-ground resting places of otters, known as couches, which are often located on islands or densely-covered ground near riverbanks.

Otters also dig burrows, called holts, in riverbanks, or in the root system of trees where they rest during the day. Holts often have many different entrances, some of which may open underwater.