Otters at Clodock Mill
Otters are very secretive animals, usually only active during the night. In the past 13 years we have seen otters on only 4 or 5 occasions, but they regularly pass up and down the river once, twice or sometimes three times a week. So how do we know that they have been here if we don’t see them?
Often in the night you can hear them calling to each other. They make a repetitive, high-pitched whistle, similar to the call of a bird.
The most common visual clue is spraint – that’s otter poo to you, kids. Otters mark their territory by leaving spraint on prominent rocks alongside the river. Otters live mainly on a diet of fish so their spraint is oily and full of fish bones. Occasionally spraint contains fresh water limpet shell or crayfish legs. Otters also hunt frogs, especially in early spring when frogs gather to mate and lay their eggs. Otters don’t like to eat frogspawn so they disembowel pregnant frogs and leave the spawn behind.
At Clodock they leave spraint at the weir, on a large rock beside the Mill and on a raft that we use to detect the presence of mink. By visiting these places each morning we can see whether an otter has been there during the previous night.
Sometimes we see their tracks in mud or fresh snow. The paw prints are rounded with five toes showing, unlike the longer four-toed prints of a dog or fox.
Otters enjoy playing and when it snows you can often see where they have tobogganed over the weir or down the riverbank on their bellies.
When the mill weir was washed away in 2012 the otters rarely visited this part of the River Monnow. Shortly after we repaired the weir in 2013 the frequent otter visits began again. The deep pool above the weir is beneficial to the trout and other fish that the otters depend on.