Too much disruption?

I've been away for the past few days in Scotland so this is the first time I've had a chance to update the blog. The weather has taken a more wintery turn at last, the wind is more biting and the slippery, sticky mud that makes walking so difficult has been turned to a sparkling granite-like rock.

There has been a good deal of activity on the river recently but not by otters, its human in nature. This is the time of year when the various habitat management agencies are out in force to cut back last years growth of trees and shrubs that fringe the waterways. I guess the idea is to open up the waterways and to ensure they don't become clogged with vegetation. However the level of clearance in some areas is quite extreme. Not only removing valuable habitat for otters but also for other animals such and water voles, deer and foxes.

All this 'tidying' work has coincided with an obvious reduction in otter activity. There has been little new sprint visible and neither of my cameras have captured anything for a couple of weeks. Whether this sort of work with chain saw, tractor and hobnail boot has disturbed the otters I can't say but in all the areas I've been monitoring, the work has removed a considerable amount of cover and created a great deal of daytime noise and disruption. This can't be good news for the otters. Denuding the riverbanks and surrounding areas make it more difficult for otters to maintain their usual state of total invisibility but more importantly removing all the low level brush and brambles means that there are far fewer potential sites for temporary holts.

A steep bank at the top of which I found a
very fresh Spraint. 

So - for the time being - the otters may have moved to other more peaceful areas.

There have been positive signs here and there however. As I said earlier I've started to monitor a second area further down river from otter valley. Here there are still good signs of activity although even here the chains was and bonfires of fresh green wood have also been blazing. In fact there has been more clearance work here than in otter valley itself.

I've identified a few new sprinting sites including a very public site on the edge of a frequently used public footpath and at the top of a very step river bank. I've watched this location on and off for a while because there are clear signs that something moves through this area on a regular basis. Today I got some good confirmation that it is indeed used by otters. You can see from the image just how steep the bank is at this point. My dog is looking directly at the spraint which is very close the the footpath.

I have never seen sprint here before and I'm not sure if this is a one off or a regular spot. Its quite possible that it is a regular sport and that the sprain simply vanishes as a result of all the pedestrian through traffic.

Very fresh spraint found close to the public footpath

Otters like to leave and enter the river close to places where there is a lot of water movement, where the water course changes direction or where there is a new channel. This location is no exception since it is right next door to a large weir gate. The otter leaves the main river channel here to cross the path and enter another side channel.

A little further along the main river widens and flows more languidly beneath a major trunk road which crossed the river. The footpaths pass  under this bridge disappearing around a broad bend into open meadowlands beyond.

Otter footprint. Here I think we can see a good
impression of the Right Hind foot and just below it
and to the left a Left front foot impression

Beneath the road bridge there are two areas of mud and stones at the foot of the reinforced embankment. These lie behind a set of barriers which make it impossible for most people and - more importantly - dogs to gain access to the river. There is a drop of about 1m. In the mud I could see a really good selection of spore prints which I'm certain are otter. These two areas on stoney mud on both sides of the river are a really good stopping off point for the otters. Much of the river bank along this stretch is inaccessible to them and the central river channel is very deep so these mud islands are essential for a short break and to quickly dry the fur perhaps.

I did manage to get a couple of snaps of the footprints but I think I'll try to get some better shots or maybe take a plaster cast if I can.

New areas to explore

The mild weather continues to lull everything into a false sense of security. Will winter ever make and appearance. We have barely seen a frost this winter and the grass continues to grow so it may be out with the mower soon.

Even the wildlife appears unusually excited for this time of year. Instead of conserving energy and keeping warm everything is acting as through spring has already sprung. The birds are gathering in groups to sing and chase one another through the hedgerows with large flocks of Blackbirds, Magpies, tits and finches all busily displaying to one another and enjoying the warm conditions.

Out on the still waterlogged meadows the herons still sit, their heads grumpily hunched into their shoulders. I saw around 5 in the same field this morning. Unlike earlier in the week the day started with a strong southwesterly wind and thick grey clouds. Day broke reuluctantly as the sun struggled to make any great impression of the heavy cloud layer.

I retrieved the memory card from the camera positioned underneath a small bridge where I first successfully captured footage of the otter. Sadly nothing at all captured this time. The other camera which is now focused on the concrete rock by another small footbridge is still in place and there was no sign of fresh spraint so I felt that camera be.

I checked the white sand bags and here there was fresh spraint so the otter has moved through this location recently. Moving on the the river channel by the Saxon church I checked the new sprinting site just below the road bridge. A reasonable fresh sprint is still visible on the rock in the river but there are no signs of fresh sprinting here either.

Moving further down river I checked out one of the other sprainting sites by the main river channel but much closer to the more urban area. Here there was a very small fresh spraint but blink and you would surely miss it.

Today I also checked out a completely new location. Basically i'm getting concerned that by sticking to such a small area close to home i'm limiting my options too much. Plus I have very limited access to much of the area that the otters frequent. As I mentioned before I have made enquiries to gain more access but even the local WildLife Trust weren't prepared to help out so I have to look further afield.

This has proved to be quite a good move. The new area I've selected is much easier to access and looks like ideal otter country. Open countryside with meandering channels criss-crossing meadow land with lots of waterside trees and thickets for cover and tall reeds along the river bank. This looks like the ideal sort of otter habitat. The channel is shallow with a stoney bottom in some placed but deeper and more silty in others. The banks of the river and shallow making it easy for otters to move in and out. On one side we have tall reeds and grasses on the other low cropped, tussocks of grass which the otters may like for sprinting.

An ideal otter habitat.

On closer examination of the right bank of the channel I became quite excited, it looked like there had been quite a lot of otter activity. Along just a sort stretch I located 4 good sprainting locations and evidence of a lot more activity besides.

According to many experts in the field when there are no good locations for sprinting to be had otters will make their own 'mound' out of dead grass or grass roots. Others see this form of activity as just a different sort of territory marking referred to as 'sign heaps' these are usually small mounds of sand, gravel, mud or vegetation and crowned with or without spraint. Sometimes these can be very large, sometimes very numerous. when the activity becomes very intense nobody seems able to offers much of an explanation as to why the otters do this. In this new location there is so much of this sort of activity going on that it demonstrates a considerable amount of industry on the part of the otter. Long my small stretch of stream these mounds can be found almost every 10 meters or so. Most look like mud scrapings but some are very distinct mounds. Some, but by no means all are anointed with spraint.

A classic otter 'sign heap' anointed with Spraint.

This 'sign heap' is a text book example and almost looks as if the otter has carefully lifted a small piece of turf with a spade, carefully turned it up-side-down and sprainted on it.

Not all the sprainting sites along this stretch of river look like this since there are other locations where the otters does not even try to make a heap. In another location the otter appears to have tramped on a nice wet muddy patch to make it good and flat then sprainted in the middle. Although this looks raised in the picture it isn't really and the otter has sprainted in the middle on top of some in situ weeds growing on the river bank. The thing I really like about this shot is the clear footprints all around this patch of mud which suggests the otter has spend time trampling it all down prior to sprainting. Its a shame the paw prints are not clearer since it it difficult to see the 5th toe but I think it is there.

A little further along the course of this stream I then came across a large area of Juncus influxes on the right bank of the stream through which there were numerous small tunnels leading to large areas off flattened grass along with some signs of scraping here and there. This very much looks like an area used by the otter for grooming. Otters don't just groom themselves by licking and nibbling their fur, they also need to dry the fur which they do by rolling and squirming about on the ground and rubbing against logs and vegetation. This would clearly account for the large areas of flattened grass in amongst the stiffer Hard reed stems.

A possible grooming site

So after a rather frustrating week what with one thing and another this new discovery is really exciting. I'll have to keep a close eye on this new location and see if I can identify any good locations to rig up a camera.

I did collect some spraint from this location so it will be interesting to see how this compares with samples i've taken further upstream.

A week of frustration

The last few days have been a bit hectic, as it always is in this period just after Christmas. Consequently I haven't had as much time as i'd like to hunt for otters.

I decided to move one of the remote cameras that I'd set up to try to capture activity on the white sandbags where there had been quite  a lot of activity in the past. I'd fixed the camera on the opposite bank of the river but the distance from the target spot was a bit too far so the Infra Red flash was not powerful enough to illuminate the area adequately. It was triggered on several occasions by something but it was impossible to see anything clearly.

However its not all bad news i did manage to capture a couple of shots which were quite nice. The first a very nice looking fox which may be the same one I've captured in the past.

Another slightly unexpected animal to pass by was this cautious looking Muntjac Deer. Although not a native species in the UK they are now quite widespread. I've never seen one in this location or in any part of Otter Valley for that matter. They do occur locally in woodland about 4 miles north of this location. In this mixed woodland area there are quite a few Muntjac but they are always cautious and not always easy to see unless you are very quiet.

The other camera which i'd already moved slightly to give me a wider view of the area where i'd successfully captured footage of the otter in the past hasn't yielded anything new on the otter front. This has been a bit disappointing but I feel sure i'll capture something new soon. There has been quite a lot of human activity during the day in the area. There has been a great deal of tree management going no, not only clearing up after the recent gales but also general winter tidying along roads and pathways. Wether this might have put the otters off i'm not sure. 

I did capture quite a nice daytime shot of this Great Spotted Woodpecker inspecting this old post for potential grubs. The daytime colour is a bonus and really shows how colourful these birds really are up close. You can also see how effective the black and white markings would be in the dappled light of a large tree. Breaking up the outline of the bird and making it blend into the pattern of light and shade as it explores.

Anyway back to the otters. I have seen fresh spraint so they are still active in this area so I'll have to persevere a little longer. The main problem at the moment is where to place cameras so that I can monitor movements and hopefully learn something of their habits or routine as they pass through this area. Most of the locations I've used up til now are slightly off the main track this makes it easier to place the cameras safely out of the way but now i'm running out of options. I had hoped to gain access to an area further away from the main public areas but sadly my request for access was denied. 

Therefore I have to put my cameras in much more public areas and will have to take the chance that they may be discovered by other people. I have two new locations in mind but it is incredibly difficult to hide the camera. The first location I've selected is a small concrete rock which sits just to the side of a small bridge that passes over a small river channel regularly used by otters. 

From my observations I think the otters are quite active in this area. They often seem to cross between the main river and this smaller channel but also seem to access a large area of slightly marshy ground to the west of this river channel that winds through the fields and farmland from the spring behind the church to the North West. As you may remember otters have helped themselves to the stock in the fishery that lies behind the church so we know this is a potential regular route for the otters.

Earlier this week I did locate a new sprinting location along this river channel and have been watching this rock by the footbridge almost daily. Setting up they camera has been problematic since there are few locations to attach the camera without it being totally obvious to passers by. Not only this but there are few things to attach it to that allow me to point the camera at the sprainting rock. After quite a considerable amount of messing around I did finally manage to fix the camera in place although actually getting it to point at the right spot after securing it to a small tree and attaching the security cable to it was a real puzzle. In fact i didn't manage to get it right the first time so had to return a day or two later to adjust the position after review the first captures which seemed to be pointing at the water and not the rock. Setting up the camera securly is a real problem sometimes. I have just sent off for another tree bracket which you just screw into a tree or post that has an easily adjustable head to make positioning much more straightforward. That said its not always easy to find a nearby tree or post.

Night time visitors at the fishery

A tiny insignificant stream emerges from a spring high on a hill just above a small Saxon church. On its way to the church it first feeds a watercress bed, then a series of small lakes before its two thread like arms split in two and encircling the church so that in sits as if on an island. The two ribbon like arms then merge just beyond the churchyard to form a more substantial tributary that winds its way through farmland down to the main river in the valley bottom.

One of the lakes above the church has been turned into a small fishery stocked with some beautiful Rainbow Trout many of which weigh in excess of 9 - 10lbs (4-5Kgs). I watched as a one fisherman landed an enormous looking Rainbow trout that weighed 10Lbs. Its thick slim covered body glistened in the morning sunlight and the rich rainbow colours of its back shone. I was visiting the fishery because i'd heard that they had been visited by otters recently which had taken unto 50 prize specimens from the lake. It is staggering to think that even an otter - which is quick a powerful animal - could manage to haul one of these beast from the lake. Apparently it could however and they had recorded the animal on video.

The Low level electric fence designed to deter the Otter.
Would an inquisitive otter manage to break through?

Otters clearly explore far and wide in pursuit of prey and a large lake full of torpid over fed and over sized  Rainbow Trout is like a trip to the local Resturant for them. These great lumbering fish probably don't move all that fast so are easy to catch. For the otters eating out every night at their local fish restaurant is clearly an appealing option so much so that the owner of the fishery has had to install a low level electric fence at great expense to keep the Otters out.

According to the manager of the fishery most of the otter activity happened in September and October last year and since the installation of the fence they have apparently been untroubled. Thats not to say that the otter gave up. It was seen trying to work out how to circumvent this new security perimeter but so far has not managed to work it out or not that bothered. On a quick walk round the perimeter myself I could see numerous placed where a determined otter could gain access if it showed real determination but so far - fingers crossed - the fence is doing its job.

Talking to the fishery manager and a local fisherman they told me that the Otter was quite large. It could be that this is a dog otter especially considering the size of the fish it took from the lake. They also mentioned that it appears that the otter only ate the internal organs and heart leaving the meat untouched. This is reported by many fishermen and I'm not totally sure why this should be the case. In could be that because otters only have quite small jaws they tend to bite larger prey just behind the gills where the flesh is easier to get its teeth into since the fish is softer and easier to hold on to here. Since the organs such as the heart and so on are here too it stands to reason perhaps that they might go for the iron rich offal first. I have also heard that when tackling large prey they will often bite the fish on the snout since they can't get purchase any other way since their mouths are too small.

I would like to stay in touch with the fishery owner here and perhaps monitor what happens in the future. I may even set up a camera here to see if the otter is still patrolling along this part of the river.

A new location for Camera 2 and more observations

The weather is still extremely mild at the moment. It feels more like spring than winter. The mild conditions have been good for birds and other wildlife. In stark contrast to last winter which is unusually harsh, this year food appears to be in good supply, plants are still green and actively growing and insects are in plentiful supply. Whether this is good for the otters or not its hard to say but my guess is that the warm conditions must make the exertion of hunting more bare able for them. Since otters must manage their body temperature carefully warm weather should - in theory - extend hunting hours somewhat. Of course with such mild weather we have considerable quantities of rain in the last few weeks. This brings its own problems for otters. Its important that they keep their fur in peak condition and need to dry out completely between hunting sessions to ensure they don't cool down too much. Consequently they may be less inclined to hunt for long periods during periods of prolonged rainfall. At the very least they will have to find shelter at regular intervals to allow them to keep warm and to dry out.

Following my success in capturing some footage of an otter on camera 1 which I had moved to a site underneath a small timber built footbridge I decided to reinstate the camera at the same spot but moved to a better position so that I can get a wider shot to see what the otter is doing under the bridge. Getting it into position was not easy though having to lay flat on a 2 inch piece of timber jutting out over the water and a large area of really deep mud which I could not get purchase on. Even in this precarious position, I still had to stretch to fit a screw in camera bracket into a large cross timber beneath the bridge. All-in-all it took me about 20 minutes to set the camera up so I hope it yields some good shots.

It struck me as interesting in the last Post that I captured the otter at the same location 2hrs:30mins apart. This might suggest that the otter is patroling quite a small area or is perhaps returning to a nearby holt or resting place following its hunting expedition down river. It will also be interesting to see if I capture any footage on Camera 2 which was left in its current, slightly exposed location monitoring activity on the sand bags.

I've also collected 3 new sprints for analysis and I'm planning to set up a new page to record my findings each time i collect a sprint and attempt to analyse the prey content. I'm also going to set up another new page to record all observations including spraining, video capture and footprints. I'll also record new sites as and when I discover them.

Success! My first Video footage of an otter

I was beginning to believe that my efforts to set up a remote camera to capture footage of my local otter population were all going to end in disappointment.

I thought I'd carried out quite careful recognisance of the area and thoughtfully chosen some of the best locations to set my camera traps. Of course none of the ones I through would yield good results have come to anything so far. However you may remember that I mentioned that I'd set up one camera beneath a small bridge where there was quite a lot of apparent otter activity. To be quite honest I wasn't too sure whether I'd capture anything at all there. But, would you believe it, this one has come up trumps. Bingo there she is - I assume its a she a) the otter doesn't look that big - and b) it is usually the females that stick to more defined territories so the betting is its more likely to be a female.

This footage was shot at 1am on 6th January 2012

And just when you think its all over the otter comes back a few hours later. Again I'm assuming its the same otter here. Has she been foraging further afield and returned to this location because its particularly good, or is this perhaps close to a favourite resting spot or Holt.

This footage was recorded at 3:39am on 6th January 2012

Its not all been that successful however. I really did have high hopes of the Camera I carefully located to watch the sandbags the otter enjoys grubbing about on and often leaves a sprint there too. Neither has there been much sign of any new sprainting nor any footage from Camera No 2. I'll leave that in-situ a bit longer to see what happens. I'm sure the otter will appear there at some point. In the meantime I'll have to decide whether to move Camera No 1 or to try to relocate it a touch to see if I can bet a better - wider - shot of the otter. This might help to understand what it is doing and where it is going. I think its just getting back into the river again but it would be nice to get a better shot if possible.

In fact the only interesting footage i've managed to capture on Camera 2 is this nice footage of a passing Fox strolling along the river bank looking for opportunities to feast on some unsuspecting mouse or water vole. Night time on the river is certainly busier than you might think. Nature is never still, it is constantly on the move always ready to take advantage of what ever lies just around the corner.

My First Attempt and Otter Spraint Analysis

On returning home from my wind blown expedition to set up my new remote camera I took the spraint sample I'd recovered from sprint site 1 and placed it in a new plastic vessel ready for processing.

I have been told by an otter expert that one of the best ways to break down sprint is to dissolve it in warm water using sterilising tablets used to clean dentures. Simply add enough warm water to to cover the sprint then add the sterilising tablet and leave it over night to work its magic.

The next morning the sprint should be completely dissolved and all you then need to do is drain off the excess water to leave the solid remains behind. And yes that is exactly what happened. You can then leave these to dry so that they are easier to handle but some people say that they can dry out and become distorted so it is easier to identify parts when still wet. I left mine to dry out.

What you are then left with is this.

What is left of the sprint after processing over night.

It was then a case of using my microscope and a pair of tweazers to pick out the bits that were most obvious or easiest to identify. One good tip is not to tip it all over the floor like i did after having sorted all the bits out. I lost quite a few in the process but managed to salvage those listed below. Please not in the images below the background is made up of a 1mm square grid for scale reference. Its amazing just how intricate and sculptural these tiny bones can be when you take the time to look at them closely.

Trout Jaw With Teeth	I think the most obvious thing i found was this Jaw including teeth. There was some debate as to whether or not this was a Pike Jaw but i don't think it is so, for the time being I'm calling it a trout. Note the grid behind this specimen is a 1mm square grid for scale.
Anterior View - Thoracic Vertebrae Lateral View - Abdominal or Thoracic Vertebrae	The small vertebrae I think also come from a trout and not a Pike this is because they have honeycombed Centrum with ribs. This indicates Salmonid (trout) rather than Pike which has no ribs. The ribs are hard to see in the photos but using a magnifying glass you can see them.
Lateral View - Caudal Vertebrae	Another vertebrae from a trout this time back end. The Caudal region, towards the tail end of the fish. Again I think this is a Trout.
Anterior View - Caudal Vertebrae
Unidentified bone Unidentified bone	These two images are of bones I can't identify

Spraint Watch

One of the main tools the enthusiastic otter watcher has to determine how active the otters are and where they are is to track them using Spraint or otter poo. Otters mark their territory not only to announce their presence and ownership of a stretch of river but perhaps also to give themselves signals to guide them as the traverse their territory endlessly searching for new hunting opportunities and exploring new uncharted avenues yet to be navigated.

Luckily Otter Spraint is quite distinctive although sometimes hard to find. Fortunately otters often leave their little cairns of poo in quite prominent places. As we humans like to leave human cairns - fortunately made of rocks, not poo - on the tops of large hills or mountains so otters like to leave their own markers on hills and prominent landmarks, at least from the otters point of view.

Large bolders, tussocks of grass, logs and sandbags are all common places of significance for otters. You can tell if a sprint is fresh or not by its consistancy and if you are brave enough a quick sniff will tell you whether its otter poo or than of a mink or even a fox that you have on the end of that stick. Otter poo does not smell unpleasant. It smells faintly fishy and a bit oily or musky but certainly not offensive.

A NIce fresh otter sprint example. I'll take this back and
have a go at analysing the content

To that end I have identified about 5 - 6 really good sites locally which I'll try to check regularly for fresh spraint. There are many other locations where the otters seem to spraint but these 5-6 key locations are used quite regularly so we may be able to determine some sort of pattern of movement by monitoring these. Another thing I'm also going to have a go at is spraint analysis. By looking at the bones within the sprint you can try to determine which prey species the otter is taking. This may help to determine where it is hunting or at the very least which prey animals it likes best.

Setting Up a New Remote Camera

Negotiating the fallen Beech tree blocking the path

Another year and - after the long Christmas break - a new working week begins with the coal black clouds of a horrendous storm, howling gales and torrential rain sweeping in from the southwest and extending the darkness of night well on towards mid-morning.

My plan today was to leave early and set up a new remote camera at a location I have been watching for several weeks. But, what with the driving - near horizontal - rain and brutal gusts of wind battering in get in through the front door like an early morning raid by special branch I decided to leave my first Otter Watching trip of the new year until later on. 

By 12 noon the wind had dropped and the the rain far less penetrating than first thing. So, I gathered my things together and set off towards my chosen location to fix up my remote camera. I have been observing this site on and off for the last few weeks and noticed quite a lot of otter activity. This must be a good place to set up my first camera of the new year. In fact I had already had another camera in-situ for a couple of weeks focused on a small pool just behind a timber boardwalk which runs for a short way alongside the river. Sadly this initial test run was not very fruitful in terms of otters all I managed to capture was the rear end of a moorhen and a short sequence of a Robin. Not a great start but i think this is mainly because I'm concerned not to make the locations of my cameras too obvious. Not that the otters might get camera shy or anything but Humans are more likely to interfere if they can see them and my chosen location is a bit too public for my own piece of mind. Consequently when I first set up my camera for the test run it wan't really pointing in the right direction. 

The group of white sandbags along the riverbank

The reason I chose this location was because I know the otter visits a short run of white sandbags which are set into the river bank just beyond the boardwalk. These seem to restrict the flow of water into a small channel which passes beneath the boardwalk. This means that the water makes a playful bubbling sound as it flows between the sandbags and some timer siding which keeps the channel from collapsing.

Otter Spraint on top on the white sandbags

Setting up a new remote camera.

The otters seem to love this group of sandbags. Not only do they regularly sprint on them but they have also taken to digging about in them and pulling them apart. Otters are often attracted to noises or to the sound of water where it flows more quickly or changes direction. My reasoning therefore was that perhaps the otters come to this point to slip down into the channel and consequently into the small pool behind. This clearly is not the case or if it is they haven't done this in the last two weeks. My new plan therefore is to move the camera and to place in at a new location that looks directly at the group of sandbags. If the otters arrive as they appear to do quite regularly I will be able to see if they enter the pool behind the boardwalk or stay within the main river channel.

So I have set up the new remote camera which I have had to place in a more open location. The camera is a infra-red camera which is trigged by a heat sensitive PIR unit built in to the camera housing. Should anything warm pass by this will trigger the recording of a 10s video sequence complete with sound. To try to keep the unit safe I've had to put it in a security box which I have screwed into the end of a large fallen tree stump. I've then disguised it as best I can without obscuring the lens with grass and sticks so that it blends into the surroundings a bit more. This seems like a a great location to catch any otter activity on the sandbags so we'll have to wait and see what happens over the next week or so.

I have also placed another camera under a small bridge near-by since there looks to be a lot of activity under the bridge which is on the direct route towards the sandbags discussed earlier.