Another Life: There's an eye-catching hummock of grass on the bank above the pool where the mountain river runs into the strand. It's taller and a darker green than any grass around and will stay that way all winter. Visiting it this morning, I found - as I had greatly hoped - a territorial offering perched on the top: a fresh dropping from an otter gleaming in the sun.
Lifting it - delicately - I could discern fragments of fine fish-bones (eel, stickleback?) along with the faintest whiff of musk.
It's some 25 years since a young English couple knocked at my door, keen to share their experience of travelling Ireland, looking for just the same thing - otter spraint (as the droppings are called) on riverside rocks or grassy hummocks on banks below bridges or along lakeshores, or perhaps the animal's tracks impressed in mud.
Peter and Linda Chapman were researchers for the Vincent Wildlife Trust, the UK conservation charity, and carrying out the first survey of Irish otters. In England, the animals had undergone drastic decline, only now in substantial reverse: the Trust was concerned to know the picture in Ireland.
The Chapmans' survey, published in 1982, was wonderfully encouraging, especially when matched against trends elsewhere in Europe.
Of more than 2,000 sites surveyed, otter signs were recorded at some 90 per cent, with rather less in the more heavily populated and polluted eastern counties. A decade later, a partial Irish resurvey of sites in the Republic found little change.
As the century turned, however, surveys north and south began to find a different picture. In northern and eastern Ireland, the presence of otters began to fall off. Even around Galway Bay, the sites with their spraint or tracks had dropped by more than 15 per cent in 20 years.
Now, a survey for the National Parks and Wildlife Service (NPWS) of 525 sites spread across the Republic has confirmed the decline of Lutra lutra in one of its last European strongholds - a drop of 18 per cent over the 25 years. The figures are best for the south-west (almost 75 per cent of positive sites) and worst for the east (just 60 per cent). There's some consolation in that the decline was fastest in the 1980s and has been slowing down a bit since then.
The survey was carried out by Mike Bailie and John Rochford, of TCD's Wildlife Ecology Group and, published by NPWS as a downloadable manual (www.npws.ie), it has intrinsic interest as an example of wildlife research and its methods. But its results, which are analysed every which way, still fail to explain why otters are declining.
Water pollution - at least of the usual rural Irish kind - doesn't seem to be an answer: the otters, if anything, were happier with "slight" pollution than either none or a lot.
Neither human disturbance nor intrusive bank maintenance - both of which have increased over the years - could offer any significant match with otter absence. Even at 13 sites where otters had been hunted or harassed, there were otters around at 10 of them.
What about mink? It was in Britain, in particular, that feral mink were blamed for "driving out" the otter through some kind of competition.
But mink happened to be spreading just at the time that toxic chemical pollution was poisoning the otters: when it was removed, they slowly began to recover.
In Ireland, too, after 1981, mink were spreading throughout the midlands and west. But while mink were obviously present at 80 of the 525 sites in the new survey, there was no relationship with the presence or absence of otters.
On our rivers and lakes, indeed, the droppings of mink and otters can often be found almost side by side. The otter, with superior speed and underwater vision, takes the bigger, faster fish. Because it's so easy to collect and analyse the spraints, more is known about otter diet than any other aspect of its biology or ecology. The studies show how varied it is, reflecting local or seasonal prey rather than any strong preferences.
In the new survey, seven kinds of fish were the main class of food, along with feeds or frogs or crayfish at particular times.
But there were a few changes over the 25 years - fewer sticklebacks and frogs and more crayfish and mammals (rats, mice and little lagomorphs - hares or rabbits).
How many otters are killed at night by cars?
That isn't known, but it's a lot and increasing, and the loss of even a few animals from populations isolated by rural and waterway development could have dramatic long-term impact. Recording and collecting dead otters will be part of future monitoring. And the next otter survey, in 2010-2011, will check 1,000 sites throughout the island.
