Analysing otter spraint

Guest blog post by Community Science volunteer Barry Soames.

Moors for the Future have a new Community Science Project, looking for signs of mammals in the uplands, the Tails of the Uplands Survey. (Follow the link for details of how to get involved and training courses available.)

Barry analysing a spraint sample

A key target species is the otter, one of our most attractive and endearing mammals, which nearly disappeared from England in the 1960s and 1970s, but which is now starting to recover across much of the animal's former range.

As I have had an interest in looking for signs of otters for over 20 years (when working in Scotland), I decided that I would like to get involved.


Evidence for otter presence is indicated by a number of signs, one of which is their droppings, known as spraint. As well as indicating presence, analysis of spraint can help us find out what the otters are eating. Traditionally this was done by examining spraint under a low power microscope, and identifying bones (and other undigested material, such as fur and feathers).

However, nowadays, more sophisticated methods are available using DNA analysis. It is interesting to compare results of both techniques, and I have been examining samples from which DNA has been extracted and sequenced to identify prey items. The genetic analyses were performed at the Molecular Ecology Laboratory at the University of Sheffield as part of the Otterly Amazing project run by the Sheffield and Rotherham Wildlife Trust.

The first step in identifying prey remains involves cleaning the spraint. Otter spraint tend to be surprisingly sweet smelling, with the remains embedded in a sort of oily matrix. To dissolve the matrix and leave the cleaned bones, I used denture cleaning tablets. The spraint is dropped in an inch or two of hot water in a beaker, a denture tablet added and then left overnight. After the spraint has been cleaned in this way, it is then filtered to leave just the bones, and any fur.

Sample '119' contained mainly fish bones

Not all the droppings collected were otter spraint, for instance at least one specimen seems to be mink. I found out that my cleaning method only really works well with otter spraint, other droppings often had to be teased apart using tweezers.


Once this is done, the harder part comes in - identifying a small pile of assorted bones. To do this, I started with a very useful Mammal Society publication, "A Guide to the Identification of Prey Remains in Otter Spraint" This small booklet is mainly aimed at identifying fish bones, and concentrates on those bones which have the clearest differences between species. Much of the booklet deals with caudal vertebrae (the parts of the backbone in the tail), with additional clues coming from parts of the jaw, particularly pharyngeal teeth (teeth found on the gill arches).

This sample was probably mink scat, with mammal remains, in particular field vole, having been identified from the teeth and jaw remains.

So far I have identified bones from minnow and bullhead, as well as crayfish shell. It is noticeable that the prey identified so far has been of small fish, compared to the larger fish found when, several years ago, I examined spraint from rivers in Scotland. Not all the material examined was from otters, with one sample consisting mainly of fur with a few bones. Parts of jaw and teeth found in this sample enabled identification of field vole. (This dropping would seem to be mink).

If you would like to see some of the results, I have a page on my website for results.

Top tips for entering our photography competition

Here are 6 top tips for those thinking of entering our 'Water in the Uplands' photo competition: http://www.moorsforthefuture.org.uk/community-science/competition

1.  Slow the flow

Reduce your camera’s shutter speed to catch the dreamy effect of water in flow. 

A tripod is a handy piece of kit to keep your camera steady, but alternatively use a small bean bag or even a folded up jumper to sit your camera on. 

Use the self-timer function so you can go hands free, ensuring the camera doesn’t move while it’s recording the shot.


2. Beauty in the details


Look more closely at water and you’ll be amazed by some of the little details to be found.

Capture bubbles below a waterfall, reflections in puddles and get really close to discover the world of water droplets.










3. Water in the landscape


Consider the wider landscape and make water a part of the bigger picture.

Think how it has shaped its surroundings whether naturally or by the addition of man-made structures like bridges and weirs.





4. Go abstract

There’s so much potential for creating abstract images of water.

Create patterns from a flowing waterfall or focus on ripples in a calm pool.














5.  Winter wonderland

Winter is a great time to photograph water as the cold takes hold to create ice and snow.

Get out early after a cold night and capture incredible ice formations clinging to plants and rocks.

Alternatively take a break from sledging after a big snowfall and capture incredible winter scenery.







6.  Life giving water

There are many plant and animal species that rely on the habitats provided by the water in our uplands.

Capture beautiful creatures in their watery homes or look at plants like Sphagnum mosses that keep our blanket bogs saturated.

Tom Aspinall

Moor Mosses and Sphagnum Sorting...

This week the Community Science team was very lucky to be visited by ecologist Dr Ros Tratt from the University of Sheffield, who spent some time with us putting mosses under the microscope -  and putting us through our paces in the field.

We spent time separating small samples of vital peat forming Sphagnum mosses from other mosses, and then identified them to species level by looking at their typical characteristics - size, shape, colour, leaf shapes and orientations and other details which can be seen using a hand lens or a microscope.

All this activity was in preparation for our new citizen science survey of Sphagnum - The Big Moss Map, which will be launched this autumn. If you're interested in learning more about moss; why it is important and how to identify it, then watch this space...