Friday, March 26, 2010
The Otter (Lutra lutra)
Ireland and Scotland are strongholds for the Eurasian otter (Lutra lutra) which is endangered across most of its range. In Ireland it is widespread and relatively common but generally goes unnoticed. Along inland waterways otters are nocturnal and often the only signs of their presence are their spraints (droppings) and sprainting sites. However, coastal otters are diurnal and their activity is a function of tidal rhythms. They generally hunt for food at low water and are most active for the period one hour before low tide to one hour after. Ireland has quite a big tidal range of around 4 metres. Hunting is obviously more successful when the dive time is less and the prey are concentrated into a smaller volume of water. So the best time to watch them is around low water when they are busy fishing and often quite tolerant of an observer watching from the shore. Their preferred food is eel or eel-like fish such as conger eel or butterfish. However, they are opportunistic and will take a whole range of fish and shellfish species if they are available. Other common food items are rockling, blennies, gobies, salmon, trout and crabs.