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Otter surveying

Otters are elusive creatures and the chances of seeing one in the wild is very rare. For otter surveying, we therefore look for signs of otter such as spraint (droppings) and footprints.

Spraints and other secretions

otter_spraintSPRAINTS are made up of clearly visible fish bones and scales, with some other small bones, fur, feather and insect fragments sometimes present.  All contents are bound by a black tarry mucous.  This hardens and dries to pale grey with age.
Fresh spraint as shown in this photo on the left  is usually black and tarry and if very fresh will be sticky.  It has a distinctive sweet-musky odour, which is not unpleasant.

Recent spraint is drying out, turning greyish and may crumble when touched.  It may smell slightly ottery still.

oldotterspraintOld spraint, as shown in this photo on the left has dried completely, becoming very pale and crumbly.  It may have crumbled completely, leaving a grey ashy deposit, with some fish bones still present.  Sometimes has a slight stale ottery smell.

Tar spots are blobs or dribbles of black tar found in spraint but with no fish bones present.  These can only be confirmed if the distinctive smell is present.

Anal jelly, as shown here  is a jelly-like secretion, which smellsAnal-jelly strongly of otter and can vary in colour from pale brown to greenish or amber colour.


Mink Scats (droppings) – twisted and tapered to a point, often with hair or feathers as the most obvious constituent but fish and small mammal bones and crayfish fragments possibly visible too.  No wider that 1cm with a very unpleasant odour of rotting meat and may be mouldy.

Bird droppings – these vary with species.  Mostly pastey, sometimes gritty, rarely having fish bones in them but insect fragments may be found.

Bird pellets – these vary tremendously in shape, content and size.  Often have remains of birds, insects, animals, fish or seed pods and plants.  Sea bird pellets often will have shell fragments and waders may be very sandy.  One difference between these and spraint is that these are bound together but dry, compared to spraint which has a tarry jelly.


TRACKS — otter tracks have five toes, which arch around the front of a large pad. In soft ground claw marks and webs between toes may show. However, often only four toes show. These can lead to confusion with other mammal tracks.
Width: Female: 5 — 6cm Male: 6.5 — 7cm Cub: under 4.5cm

Mink have five toes like an otter but they are smaller and star shaped with long claws that often show. Less webbing may show than for otters.Width: 2 — 4cm. 

Dog and fox tracks have four toes only.

Click here to download an ‘operation otter’ footprint guide of tracks on the river bank.

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