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Otter Fieldcraft

By Peter Dale & Peter Guthrie

The Common or Eurasian Otter Lutra lutra, although found living in both fresh water and marine habitat in the UK, they are NOT two different species but are one and the same. They are NOT the Sea Otter Enhydra lutra from the Americas

Peter Dale and otters: In the 1980’s I became involved in a long-term project gaining 14 years’ experience of otters in the field, surveying for spraint signs, fresh water sources, couches and Hadds (or Holts), trapping the Otter, monitoring by the use of radio telemetry, spraint analysis using a radioactive isotope, trapping and assessing prey species, and this deep interest has remained with me to this day.

The sexes are normally referred to in the following context: The male as a ‘Dog’, the female a ‘Bitch’, and the young ‘Cubs’. Its Otters we’re looking for and there’s no guarantee you will find them or even see them, but this may help. First and foremost, put your ‘Otter Head’ on, think and act like an otter

Preparatory fieldwork

Get to know the otter’s patch and do your fieldwork first, locate, identify and plot all areas of activity: spirant points, couches, brackish pools and fresh water sources if watching in sea, known promontories, rocks showing above water etc, the narrows of a sea loch, not necessarily close in shore, freshwater lochs, lochans and river systems

Tracks, trails and signs

Spraint is the obvious one. Spraint points are found normally on an elevated feature level with any passing otters nose on small divots of grasses or raised piece of rock. They are normally formed as a black tarry substance, but also an opaque anal gel, which is assumed to be of a sexual nature, confirming when a bitch is receptive. Spraint contains undigested prey remains, predominantly fish. In the case of dogfish where only the liver is taken or crab remain, this if often an indication that the animal is out of condition or is ailing in some way. The smell is not what you would call unpleasant and a means of communicating the presence of animals on a patch, sexual receptiveness etc. between animals

Spraint has a number of uses: a means of communicating through smell to other otters that the patch is taken, or if a female, her receptiveness to mate or not. If spraint is washed out by heavy rains the spraint points can still be identified by the very rich nitrous green coloration on grass divots. Rocks overhanging trees at otter nose level depending where the spraint has been deposited depends on how long it remains in situ. If in the tidal zone, within say 4 hours, if out in the weather it may disappear in no time at all, if under cover, for example within a man-made structure, under a bridge or upturned boat it may last for a considerable length of time. Spraint is graded as follows: Very Fresh – within 24 hours, Fresh – within a couple of days, Old – a week or more, Very Old – a month or more.

Pads: often found in grass by the side of the road as trampled grass. As otters have a soft pad to the sole of their paws, they do not cut into the grasses as a cloven-hoofed animal (such as deer or sheep) would. They are to be found crossing a peninsular of land along the sea shore, the ox bows in rivers, with the flow taking the Otter down river does not need any energy expenditure, therefore these pads are normally used when traversing up river. Otters will cross country for many miles, normally following water courses, I have physically trailed an otter for 3 miles and by radio telemetry 21 miles

Prints: the otter is a five toed, web-footed mustelid, the fifth toe as with the webs are quite often difficult to identify, even on soft surfaces: sand, mud, freshly disturbed soil, I have found them in the peat dust that has settled in old man-made structures, where they will last for years

Track: especially in snow or soft ground, the tails often dragged leaving a long straight indentation in the substance

‘Gates’ not true gates but areas where the otter passes under stock fences and field gates, in particular the wheel tracks of vehicles, where this is identified by the lack of soil debris or the polished metal or wood on the underside of wire, bottom bars of field gates etc.


Couches: a resting spot normally a grass covered depression in the ground found on promontories close to open water, rock outcrops and small islands, consisting of trampled grasses usually within bank grasses which afford some shelter from the weather. Some can be found on seaweeds within the intertidal zone which are subjected to the ebb and flow of the tides.

Slides: normally found in river systems, but also along the shore, especially on high peat banks

Fresh and brackish pools of water or fresh water courses entering sea water: Otters require fresh water to rid their fur of salt when living in a marine environment, thus keeping the thermal quality of their coats in the best possible condition.

Hadd’s/Holts: mainly for long periods of rest or as a natal den for the bitch when having cubs, breeding. They are often found in extended rabbit warrens, peat banks, tree root systems, dormant badger setts, boulders clutter and man-made structures – in particular upturned boats, or disused/derelict buildings

Road crossings, and casualties: Otters come into contact with road traffic and are normally found dead on the roads after heavy rains when otters tend to move about their home ranges or when young are dispersing

Culverts: they frown on using the culverts and tend to cross over the roads leaving them open to becoming a casualty

Bridges: some having purpose-built Otter underpasses installed with fences to guide the otters in the direction of the underpass with a view to encouraging them to cross under roads rather than over the road where they once again become a casualty

Other Man-made structures: electricity transformer bays, where they seek warmth, boat houses, upturned boats, when they become comfortable with man’s presence, they will enter occupied buildings, I have been called upon many times to move animals out of occupied offices and from industrial complexes, more for the benefit of man rather than the otter

The famous Otters ‘Chain’: if you are fortunate enough to be looking down on an otter at sea, watch for the ‘Chain’, the string of air bubbles being released from the otter’s pelt under pressure when it dives. The fur consists of outer guard hair and a very thick inner layer of fine under hair which traps the air, insulating the animal against the cold. The release of this air can give an indication of the otter’s direction of travel whilst under water and dependent on depth of dive as to how far ahead of the ‘Chain’ you expect the otter to surface.

Territory or home ranges differ:

They vary in size, a dog has an estimated 10 to 15 kilometres of coast line or river systems, a bitch 8 to 10 kilometres of coast line or river systems, therefore you are not likely to find an animal or animals in the same location each day, and remember, otter activity when at sea is controlled mainly by the ebb and flow of the tide, these guys do not do 9-5 Monday to Friday.

The young consist of a litter of 2-3 cubs that will be the care of the bitch alone and remain with her for up to 18 months. They will usually disperse over the last few months, the dog cubs being the first to leave and normally driven out by its father, who is not keen on having any other dogs on his patch. The same dog will retain as many bitches as possible within his range and make every attempt to retain any bitch cub including his daughters, leaving the bitch to drive out any bitch cubs. Therefore bitch cubs are the last to disperse.

Interaction with other animals, birds and man:

There’s one cardinal rule ‘DONT DO’: The one thing otters hate are domestic Dogs so please, if possible, leave you pet at home or in the car

They will steel a fisherman catch if left unprotected. A friend fishing for sea trout left his catch on the shingle ayre behind him, only to turn and find an otter taking his catch (Scavenging) – would you turn your nose up at a five-course meal, especially if it was free? If you persist in laying out free meals, an otter will take it

There is a very different reaction when otters come into contact with Common Seal where the otter is king and often puts the Common Seal in to a panic, but when coming into contact with the Grey or Atlantic seal the tables are turned, and it is the otter that takes flight

The BBCism: There is a misconception of the animals being shy, illusive and cuddly, they are anything but, they are in fact very inquisitive, but the BBC likes to portray the otter as a ‘Shy, illusive and cuddly little animal’, and you are to ‘Speak in Whisper’s’ when in its presents, they are nothing of the kind, at the end of the day, they are carnivores, red in tooth and claw and will take your hand off and beat you to death with the soggy end, bin there, done that, seen the video, got the tea-shirt, and more importantly the scars to prove it.


 More pine martens!

Field Craft and Locating an Otter or Otters

The best form of hide is one on four wheels, your car and if you are to alight, it helps if warm, waterproof and drab clothing is the order of the day, and DON’T SLAM THE CAR DOOR

Weather and Sea conditions, it’s no use looking for otters in high sea conditions, don’t waste your time money and patience looking for otters when the conditions are not right

High water slack tide and low water slack tide is not usually conducive to good otter watching, but you’ve still a chance. Tides twice daily results in water movement usually the 4-5 hours between high and low water whether ebbing or flowing equals water movement, equals prey, equals otters

The best location to find these conditions tends to be at the narrows of a sea loch with large volumes of water flowing in or out of the basis above, the larger the body of water the more prey available to the otter

Moving on to a suitable location to watch from: find a promontory where you can scan up and down a reasonable length of coast line or river system. One with small islands is even better as this gives the animals a secure place to rest or eat large prey

On arrival at your OP (Observation Point) check all known activity points first, reducing the time wasted scanning the whole arc of your field of view

Other points to consider: The surface conditions, the best surface conditions tend to be with slight surface movement, it’s no good going to look for otters in a howling gale with a big swell and breaking waves. Yes, the otter has to feed, but your chances of seeing them is absolutely ZERO. The same is true of the direct opposite, flat calm or rain on the surface of the water doesn’t help either and daft as it may seem, it affects the otters hearing. Current weather conditions are no obstacles to otters – they will feed (they have to!) – come hail, rain or high water, they will be there

Remember the ‘Three Wise Monkeys’ – Hear no Evil, See no Evil and Speak no Evil. Use all your natural senses: watch for un natural movement, listen for alarm calls of birds – Hooded Crows & Gull SP tends to draw your attention to the animal, smell (Spraint) and touch if you have to, spraint that is

Keep the wind in your favour and the sun to one side, if possible. Try not to have the sun at your back as the otter will sense any movement that you make. Observe the animals movements and dive times, this will give you some indication as to when to move and how long you can move before the animal is likely to surface. Keep a low or very low profile, but if caught out, FREEZE, and remember: no quick movements, pointing, shouting

Initially: scan with your eyes, as you have a greater field of view, looking for what can only be described as ‘Unnatural Movement’ linger over an area for 20-30 second, as the dive time, in shallow water is in the region of 18-20 seconds, if very shallow at the water’s edge, only a few seconds, but the weed makes it difficult to locate otters in these conditions

Fix your gaze on a length of coast line and watch it for a minute or two as an otter’s dive time can be in this range when working some distance offshore, if working the weed at the water’s edge, dive times are much shorter, within seconds at times, and the animal can be much more difficult to find and view, check rocks protruding above the surface on a regular basis for otters coming out to eat or rest, and watch for that split second of unnatural movement

Using other wildlife to locate an otter


Watching and listening for other birds and animals for their reactions and alarm calls when an otter is present

A congregation of predatory big gull: Lesser Black-backed Gull, Greater Black-backed Gull, Herring Gull and Grey Herons, and now White-tailed Eagles on or above the shoreline looking down on a particular area of tidal edge are usually a guide to the presents of an otter feeding on the shore line, these birds tend to try and steel the otter’s prey or scavenge on the remains

White-tailed Eagles have been regularly observed scavenging or even stealing the otters prey either at sea or ashore, and there are records of otters being scalped by White-tailed Eagles on the peninsular, in one incident an otter was seen to be lifted clear of the water to a great height before being dropped by the White-tailed Eagle, it is not known whether the otter survived or not

Should you be fortunate in locating an otter at sea, KEEP your eyes on the subject and bring your binocular to bear, take a note of its dive times, counting under your breath using the one-thousand second principal, the deeper the water, the further to sea, the longer the dive time, the prey is likely to be small as this can be consumed easily at sea, if larger prey in the way of Lump Suckers etc., this is often brought ashore by surface swimming, the last few meters in a shallow dive, the prey then consumed ashore

Don’t become fixated on one animal, keep scanning through 360 degrees (Dalelia WTE as an example) The saying ‘Behind You, Behind You’, comes to mind

Manner of swimming: if the animal you are watching has a head like a bottle and rolls into a dive its likely to be a Common Seal, if it’s an otter, the flick of the tail is usually the last thing to disappear when the otter dives, but Otters don’t always show their tails as they dive, especially when working weed at the water’s edge, where dive times are of a short duration. Broad webbed feet, particularly the hind feet are the driving force, the forepaws and flexible tail the steering gear

The prey species in a marine habitat is often small and large fish, Three-bearded Rockling, Viviparous and Yarrell’s Blenny, Butterfish, crustacean: crabs, octopus, birds from the surface of the water, and rabbits or other small mammals, and otters will scavenge etc. They don’t tend to go for Dog Fish, but if they do, they only take the liver – can you imagine eating sand paper? Small prey taken at sea will be consumed at sea thus reducing the effort of swimming ashore to eat it, larger prey, including crabs and octopus are normally brought ashore to be consumed

Closing the distance without disturbing the animal: monitor the animals dive times, then, say that is in the region of 20 second down and 6-7 seconds on the surface, that’s about the usual time it taken an otter to consume small prey on the surface, wait until the animal dives, make your move fore say 10 second and stand still, BEFORE the animal surfaces, continue this process until you have reached a safe distance from the otter That does not mean ON TOP OF IT

Otters are not normally vocal but the calls or ‘Whistles’ can be heard over the noise of very strong winds and heavy sea conditions, in particular cubs attempting to make contact with the bitch. He, She or they will soon let you know when you’ve been spotted, with repeated ‘Huffs’ or if really annoyed, ‘HA! HA!’ given as a warning before doing the disappearing act. If cubs are present, you may be fortunate in hearing them ‘Whistle’ especially when very young, this is a means of contact between the cubs and their mother. When two dogs are fighting there is often a lot of screaming


If a family group, bitch and cubs are at sea they are all likely to dive together, unless very young cubs which often remain on the surface, as they get older and when 12 to 18 months, they will forage separately

When the family begins to disperse, the cubs are often found on the peripheries of the bitch’s home range, the first to be chased from the territory is usually any dog cub, as both the bitch and the dog will see him off, as for any bitch cubs, the chasing is left to the bitch as the dog will try and retain any bitch within his patch, including his offspring

If you are that keen, and observant, you will have noticed that otters have a throat mark, draw a blank outline of an otter’s throat on a sheet of A4 and sketch in the details at the time of observation, I have 68 throat marks on record and can trace five generation of one family tree using this principle

I should not have to remind observers, that the otter (Lutra lutra) and its respective habitats are fully protected under Schedule 5 (Section 9) of the Wildlife and Countryside Act 1981 (as amended) and under Conservation of Habitats & Species Regulations 2017.

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