On Sunday I went out on my monthly otter survey, it was a beautiful afternoon with a good light for photography, so I decided to ‘take you with me’ as it were.
My otter patch is on the North Somerset Moors, an area that feels like a smaller version of the Somerset Levels – low lying land criss crossed by drainage ditches, known locally as rhynes, and drove roads, with a wooded limestone ridge to the North.
The rhynes have SSSI status because of their rich plant and invertebrate life. A lot of work has been done to bring them into a ‘favourable condition’ and they were looking very clean and healthy. Unfortunately in some places there was an alien invader which has the potential to cause a few headaches.
Azolla or water fern, is a pretty little plant that can build up into huge mats up to 30 cm deep which exclude light from the water column. It will out-compete just about everything, even the ubiquitous duck weed, and is so undesirable that the Environment Agency have produced an app which can be used to identify and report it ( http://planttracker.naturelocator.org/ ).
The brook I survey is a short walk up one of the droves. The mud was perfect for footprints, so I kept half an eye on the ground. I have often found badger prints here but this time all I could see was dog.
I always advise people who ask about learning to recognise animal tracks to start with dog. The more paw prints you look at the more familiar they become then, when you do see something different, it almost jumps out at you.
I have seven survey sites along the brook that I check for otter signs every month. Otters use their droppings (spraint) to mark their territory, and they tend to have regular sprainting points which makes surveying quite easy if you know where to look, and what you are looking for. Most of my sites are under bridges, on large stones and ledges.
Here spraint lingers longer as it is protected from the elements and is only washed away if heavy rainfall causes the water level to rise significantly. Otter spraint is quite distinctive, it often contains scales and fish bones and has an unmistakable smell which is said to resemble jasmine tea. Mink scat, which can look similar, smells rank so if in doubt use caution!
As well as spraint I sometimes find anal jelly, often called tar because that’s exactly what it looks like, and footprints.
Otter prints can be quite tricky to identify. When they are clear it is hard to mistake them for anything else, but this isn’t often the case, and it takes a practised eye to distinguish them from dog.
Prints can be very exciting, I still remember finding two clear tracks under a bridge, one with large prints and one with small. It was the first evidence I had that the otter on my patch was a female with a cub.
Recently I photographed a very distinctive otter print with a ‘wonky’ toe. Judging by its size, and the areas where similar prints have been seen, my colleague, who noticed them first, thinks it was made by a female otter who surprised me last February by appearing on a borrowed trail camera with two cubs. She had brought them up right under my nose, within metres of a path regularly used by dog walkers. It’s unusual to be able to recognise an individual animal like this, so we are hoping to be able to use her tracks to see where she turns up and how far she travels.
I didn’t find anything nearly as interesting this time, just some old spraint that was there on my last visit. I wasn’t too worried as otters have large ranges, and although they may go several months without visiting the brook they always seem to come back.