Composite photos from trail cameras

Trail cameras take serial pictures from a fixed viewpoint and lend themselves to making composites of images recorded at different times.  These are particularly useful in showing relative sizes, as in the image above which comes from a couple of years ago.

The photo below is recent and is made from fitting together three slices of the same view with subjects that didn't overlap.  It shows a comparison of the sizes of an otter, an American mink and a stoat, three distantly related species.

The next one compares the mink and the stoat on a different camera, the size difference somewhat exaggerated by the different distance from the camera.

In the examples above the joints between different photos have been removed for effect but I usually leave them to make the point that it is a composite and not a trick photo.  The next three photos from the "weasel box" in my garden compare the sizes of a female stoat (L) with a female weasel in the first two and a male weasel in the third.  They also show fairly dramatically the size difference between male and female weasels.

These also show female (L) and male (R) weasels on different visits to the box. The male is twice the weight of the female.

The last example compares male stoat (weighing 350g), female stoat (250g), male weasel (120g) and female weasel (60g).

I notice that all the animals above are mustelids, perhaps because they are frequent targets of my cameras but also because size comparisons of related species are particularly useful.  I'll see if I can come up with something similar for smaller mammals.

Making scents of the world

Animals perceive the world very differently from the way we do.  They have better vision, better hearing and a much more highly developed sense of smell.  Mustelids in particular live in a world of scent, using it to advertise their presence and to see who else is about.  The first video, from earlier this week, shows an otter sniffing almost every plank on the bridge to work out who has been there before.

Next a less welcome mustelid.   A male mink scent-marking by body-rubbing, then a female sniffing to pick up scents, and finally the female doing a bit of body rubbing of her own.

A stoat has been a regular on some of the cameras.  It was also sniffing its way around when it came across some mink scat.

Another video from earlier this week: a male weasel went through the camera box at high speed and on his return I am sure he was scent-marking in the tunnel.  He was also making a weasel sound I haven't heard before.  A couple of hours later a female weasel came sniffing through the box and picked up his scent.

Finally, to complete the local mustelid set, a couple of badger videos, although not recent.  First a badger sniffing its way around and seeming to take a particular interest in my scent on the camera.

And a mother scent-marking one of her cubs to make sure it smells like the rest of the family. The cub wasn't impressed.

News from OtterCam

The otter cameras are in a quiet phase at the moment.  The previous cubs left in early May and I hope that the female may have given birth to new cubs last month.  Time will tell.  The dog otter was missing for a couple of weeks, probably travelling elsewhere in his territory.  That's him in the photo above, wandering past a camera.

On a camera set up to look for deer one of the otters appeared making an unsuccessful attempt to catch a mallard.  The video was recorded at dusk but the camera was still in daylight mode and the resulting noisy picture has been put through a denoise programme resulting in a rather "soft" image.

It was interesting to see the otter try.  I suspect it was surprised to see the ducks fly off, perhaps hoping that the target was a duckling not yet able to fly or an adult in eclipse.  Mallards, in common with other ducks, and geese and swans, moult all their flight feathers in one go and are unable to fly for three or four weeks, usually in July.  The drakes develop a drab female-type plumage to make themselves less conspicuous.  Here is a photo taken in this week in a previous year showing a drake mallard in eclipsed plumage.  You'll see he has lost his normal colours to be in camouflage and has a row of pins where his new flight feathers will grow.

Perhaps the otter just got the timing wrong.  Also from the past week here is a drake testing his newly regrown feathers.  He'll soon get back his handsome plumage as well.

When the otters do appear on camera they are usually just wandering by.  On this occasion the dog otter spent nearly ten minutes rolling on the moss but I have edited it down to just over a minute.  This was also at dusk and the camera changed to infrared towards the end.

Three hours later the female came and did the same so they are still very aware of each other even though they probably rarely meet.

A near miss on OtterCam

How about this for a close encounter?  I went to change the trail camera cards and batteries with my mate Brian and we stopped to look at a newly-emerged damselfly.  The dog otter must have heard / smelt / seen us and quietly slipped into the water only a few yards away.  We only realised what had happened when I looked at the videos at home.  Frustrating!

The other news is that the otters are courting.  The three cubs have left their mother although I think two of them are still around.

Two days before the picture above the dog went through the same spot whistling for a mate.

And a few hours before we were there the courting couple were caught on camera.  First the male went behind one of the cameras.  A little while later the female followed him and moments later they reappeared.  In her hurry to keep up she bumped into the camera before running ahead into the water and circling round to encourage him.  The chittering noise is one I have heard every year to attract the male but this is not as loud as this time last year.  After a bit of scent-marking and sniffing they went off out of view.

The timing of this is interesting.  This is the fourth May in a row that I have seen courtship behaviour in the otters.  Here is a fairly primitive chart to show what has been happening in the 7+ years that I have been following the otters with trail cameras, starting in February 2019.

You'll see that a pattern has emerged in the last four years with cubs (presumably) born in July - gestation is 63 days - and visible from October/November before dispersing in May as courtship begins.  Otters are non-seasonal breeders but this has settled into an annual cycle.  In the earlier years I didn't have cameras in permanently and hadn't worked out the best place to put them but even so we can see a different pattern.  The courting in February 2022 was well seen on camera but presumably didn't lead to anything as new cubs weren't seen until November that year.

Otters don't usually breed until they are about two years old and I read that the average female only lives long enough to have two or three litters.  However, otters can live for up to eight or nine years in the wild so it is obviously possible for one female to have more.  If a female died or was no longer able to reproduce I would expect there to be a delay while the territory was taken over by a new female so the chart makes me wonder if this female is already six years old and is hoping to embark on her fifth pregnancy.  If so, and if all goes well, we should expect to see new cubs on the cameras in October or November.

One other observation.  None of the three recent cubs ended up larger than their mother so I suspect all three were female.  You'll see above how much larger the male otter is.  A year ago both cubs were male and grew larger than their mother.    This is a video from yesterday and I think it shows two of the cubs still in the territory, or possibly the mother still with one cub (when she's not courting).  Notice that the first cub has a tick in its left ear whereas neither the dog otter nor the mother had a tick in the video above.  Once the videos show only a solo otter it becomes more difficult to tell who is who.

A BIG surprise on OtterCam

It's only a glimpse but is on two cameras and well worth a look.  The dog otter went past with a huge eel, almost as long as himself.  What a pity he didn't stay to eat it in front of the cameras.  I have slowed both down to quarter speed to make it easier to see the action.

Basil Dean, an Environment Agency specialist in river restoration and currently seconded as a Development Manager to the Ouseburn Way project, says he has long suspected that there are large eels in the lake as the habitat is perfect for them, so it is good to have proof.  My cameras have previously recorded otters with fish, a rat, moorhens, ducks, frogs and now an eel.  As long as it is meaty, if they can catch it they'll eat it.

Eels are a favourite food of otters but I expect most of those they catch are smaller than this.  I can't imagine that he could eat it all in one go and I suspect he didn't need to go fishing for another night or two.  The European eel population has declined by 98% over the past 40 years and the species is now on the IUCN Red List.  And it's not because otters are eating them all - the principle causes include pollution, loss of habitat, climate change and physical barriers to migration, so it is good to know that this is somewhere they can thrive (if they stay out of the reach of the otters).

In other news, as they say.  The otter cubs are still with their mother, or at least two of them are. The last time the cameras saw all three plus mother was 10th April but I can't tell if the two are always the same two.  The cub with a bad leg is still there and is almost back to normal.  The cubs are now 10 months old and are likely to disperse soon, perhaps this month.  I think all three are still around because I am often seeing a solo otter (not the dog) and quite often it is whistling a contact call.  It could be that one (or more) is already semi-independent but still in the territory. Here are all four in April - the middle cub is the one with the limp but you can see it doesn't look too bad.

And here is the latest play fight.  When it involved three cubs the mother always joined in but this time she just let them get on with it.  It's a bit disjointed as a lot of the action was off camera and it was a misty night with some of the cameras a bit steamed up but it looks like fun.

The previous three litters all left at about 10 months of age and each time it seemed that the mother initiated it by courting the dog otter.  From the timing of things I suspect that the present female has been the mother of the last four litters but I can't be sure.  Female otters generally only live long enough to have two or three litters so, if I am right, it may be that this female won't breed again.  It will be interesting to see what happens in the coming weeks.  More news soon.

It's a smelly old world

We humans have a poorly developed sense of smell so it is difficult for us to appreciate how important it is for most other mammals.  Mustelids, in particular, use scent to communicate with others of their kind, marking their territories and advertising their presence and breeding condition.  With the exception of badgers, female and male mustelids lead separate lives, usually meeting only for courtship and mating.  As they have large territories, are thinly spread across the landscape and are mainly active at night, scent-marking is a vital way for them to tell who is about and who is available.

Otter cubs are already leaving their own scent marks and sniffing others by the time they first appear on the cameras at three or four months of age.  The first video, from late 2024, shows two young otter cubs exploring their world, much more interested in the scents than the sights or sounds.

Otters use spraint (otter poo), urine or anal jelly to leave scent marks, choosing prominent features such as rocks and grass tussocks.  This is a new spot I have only just discovered.  The very first night after I set up a camera an otter turned up.

The next video shows a popular sprainting spot which is very regularly visited by the dog otter and (separately) by the mother and cubs - there is fresh spraint almost every time I look.  It was interesting to see it marked by a badger as well on this occasion - a behaviour known as "musking".

Badgers' family dynamics are rather different from otters' but they use latrines to mark their territories and they scent-mark each other to reinforce the clan smell and maintain family bonds. Here's an example with a mother repeatedly making sure her cub smells like the rest of the family, using sub caudal glands under her tail - a process called "allomarking".

Polecats are notoriously smelly to our sensibilities (another name is foulmart) but it obviously works for them.  The next video shows a polecat using urine, scat and body rubbing to advertise its presence and sniffing to see who else has been around.

The smaller mustelids are the more elusive they become.  Tracking weasels and stoats is very difficult so less is known about their territorial behaviour.  Field signs are usually very few but this weasel left a message inside my camera box.  It was also scent marking by rubbing its body along the entrance pipe as it went in and out, something that happens nearly every time.

OtterCam on Channel 5

Oh dear.  It's happened again.  On Channel 5 last night.  People like otters and television people like to show pictures of otters but why they also need a mumbling old man as well is beyond me. My main aim in making all my otter videos is to be able to share them so of course I said yes but it wasn't a comfortable experience.  After Winterwatch a year ago I was hoping it would be better - at least I didn't wear my dreadful old hat this time. 

The approach came from Lonesome Pine Productions, an independent TV production company based in Newcastle commissioned by Channel 5.  The team above (R-L) was Simon Glass, who was also cameraman for Winterwatch (but soundman as well this time), Alan Fairholm, producer, and Bunny, assistant producer.  Brian Rutter took the photos in this post.

Most of the time all I had to do was walk towards tha camera (I am quite good at that bit).

Simon also took a lot of drone footage, much of it general views of the reserve and some of me walking up and down (again).

The interview is much harder than it looks, mostly because I talk too much.  The editors need very short sentences so they can cut up the copy more easily whereas I tend to talk in paragraphs.  Added to that I am always thinking three sentences ahead so I don't lose my thread but then I do.  Fortunately very little of what we recorded was used in the end.  (If you think it was bad you should see what they left out!)

The programme was no 24 in a series of 40 on Channel 5 called Love Nature.  If you want to watch it you can see it on the Channel 5 website here.  I suppose if I got more practice at speaking in front of the camera I would get better at it but I hope that's my television career over.

The trail camera footage they used was some I have shown before in posts here and here.    To bring you up to date here is a brief clip of the family last Sunday.  You'll see the cub with the poorly leg is still limping but is able to keep up with the others.

Grooming and suckling on OtterCam

This is amazing.  In seven years of watching otters on my trail cameras I had never seen a cub being suckled until just over a week ago.  And now it has happened again - twice, and with two different cubs.  The cubs are now seven and a half months old, nearly full grown, and they should be independent in perhaps about 10 weeks time.  Last time the cub with a foot injury was the one suckling and I wondered if it might be for comfort.  The next time it was the injured cub again and I think mother was more interested in grooming herself and the cub.

The latest episode was with one of the others.  Mother had been grooming herself for about a minute before the cub turned up and the grooming and suckling went on for another two minutes.

The injured cub sticks closer to the mother than the other two who are noticeably more independent.  It will be fascinating to see how things develop over the next few weeks.

An injured cub on OtterCam

I feared the worst at one stage but this may not turn out as badly as I thought.  The smallest cub, presumably female, was limping badly two weeks ago with an injury to its right back leg or foot. In the first video you can see it lagging behind the others, wanting to join in the play fight and then getting upset when it all got a bit boisterous and one of them presumably trod on its poorly foot.

Two days later the cub appeared on the cameras on its own and could barely drag itself up the bank - a video distressing to watch that I won't post here.  I thought if it didn't manage to rejoin the mother and the others and couldn't catch its own food it probably wouldn't survive.  Later that night there was a video of mother with the two fit cubs and no sign of the third.

Since then, however, it has rejoined mother and at least one of the others on the videos and seems to be managing, although it is still limping badly.  Here is the cub with mother and one of the others.  The first camera was very fogged up.

And then something I have never seen before.  Otter cubs are weaned by 14 weeks of age and these three are now seven months old and yet mother was letting the injured cub suckle. Perhaps she senses the cub's distress and this was for comfort rather than sustenance.

Some good news is that the dog otter has made a fairly good recovery from his leg injury although it has taken two months.  Let's hope the cub does the same.

Puzzles on OtterCam

I watch a lot of otter videos and most times I can understand the behaviour but this episode has me puzzled.  The cub is obviously in mother's bad books, perhaps because of something it said or did, and it seems to be being disciplined in some way.  Perhaps the mother didn't want to be followed but, if so, she gave in in the end.  I don't think I have heard this chittering sound from a cub before, only from an adult female when courting.

The dog otter has been carrying an injury for the last few weeks.  I first noticed it seven weeks ago, having not seen him on camera for a couple of weeks before that.  He was unable to put his left hind foot to the ground and was hobbling about on three legs.  There were no signs of wounds apart from a new scratch on his nose - so a fight injury is a possibility but this would be an odd one.  It is intriguing that there were what looked like wounds on a dog otter in early December.

From the look of it I first wondered if his leg was broken or dislocated but when he rolled around he didn't seem to be in any discomfort, although his leg was flopping in a very unnatural position. Over the weeks it has gradually improved as you'll see from the video but he is still limping.  I guess we'll never know the cause and I can't even be sure it is the same dog otter as before. There may have been a coup.

I only just missed a very close encounter last week.  Only three minutes after I left this character turned up to sniff the cameras, perhaps to check it had been me.  Maybe next time I'll wait a few minutes in case it happens again.

The otters have a takeaway

The cubs are over six months old now and are growing fast but they still rely on their mother to catch their food.  As they become more independent they are less often all three close by their mother's side so when she catches a fish there is often no competition for it.  Here one of the cubs shows how to eat a raw fish in 40 seconds, mostly without using its paws.

Otters mainly eat fish of course, but being carnivores they also will be happy with amphibians, crustaceans, small mammals and birds.  Ducklings and other young birds are a delicacy in springtime but occasionally there is the opportunity of something bigger.  One night last week the mother went quickly past one of the cameras with two cubs in very close attendance and something in her mouth.  The view is brief and the other cameras missed it but I worked out she had caught a drake mallard.

By the time they reached the next camera she still had the duck and wasn't letting go. Unfortunately she then took it away as I would have loved to see how she dealt with it.  All three cubs followed, hoping for a share of the spoils.  (The moaning sound is from the mother otter, not the duck!)

The cubs will have to work on their fishing skills before they become independent in a few months’ time but I expect it will be some time before they can catch a duck.

End of year favourites - Otters

What a year it has been.  The best yet in seven years of following my local otters with trail cameras.  Selecting my favourite videos of the year has been very difficult.

2025 started with the mother otter and her two male cubs, then about six months old.  They grew rapidly and were soon bigger than she was.  These are my two favourite memories.

The cubs were with their mother on 2nd May and by the 4th they were gone and she was courting.  The courtship went on for weeks, much longer than I have read about in the books but seems to have gone to plan.  The three new cubs were born in July and first appeared on camera in November, at about four months of age.

They will be with their mother until late spring and at the moment they are appearing on camera several times a week.  Here are three recent favourites.

The otters have been dominating the blog recently so expect more videos in the coming weeks. Happy New Year.

An update from OtterCam

I am determined to make the most of the opportunity presented by the otter cubs so I am experimenting with the trail cameras.  One new camera is a Woopeak TC22 which has a number of limitations but one or two good features.  One that I like is its wide-angle view.  I set it up with one of my Brownings so that they had the same viewpoint and made this video to compare the two.  The Woopeak produces a duller, less vibrant, less contrasty picture so I have tried to match that to the Browning in editing.  The video is from last month so the cubs were a bit smaller and for most of the time only two were in shot.

One big drawback of the Woopeak is its poor night-time performance and it is overexposed when multiple cameras are shining their infrared light.  The Brownings cope especially well.  In the first part of the next video two cameras are lighting the scene and when the otters reach the water several more join in giving a brightly lit view.

I have failed over several years to get good videos of otters underwater, especially in daylight. The wide angle has some promise and might have been even better on a sunny day.  Here is the mother, each time with only one of the cubs.

I have never seen an otter in a tree before but the dog otter turned up and climbed into the base of a tree to leave a scent mark.  The camera was set to watch the bank, not the tree, and all the action was in the top left corner.  It was early morning in poor light and the image is cropped so it is rather grainy but we can just see what he was up to.  I mentioned a couple of weeks ago that he had appeared with some wounds or injuries.  He doesn't seen troubled by them but the marks over his ribs are much more obvious here.  It is difficult to work out what might have caused them.  To me this looks here much less like wounds from a fight.

Finally another view of the family from a couple of nights ago.  This time all from one camera but taking advantage of the light from the others.  All the cubs were sticking close to mum this time.

Vandalism on OtterCam

The current group of cubs are the most boisterous I have seen, possibly because there are three of them.  They are full of curiosity, especially when it comes to trail cameras.  Here's what I am up against.

When I set up a camera the last thing I do is clean the lens.  Here's the first thing that happens next.

The trail cameras give us a remarkable insight into the otters' lives, something we could never see otherwise.  Here is the mother bringing in another fish.  The delay between disappearing from view and reappearing with a fish was 18 seconds.  She doesn't seem impressed with the cub's manners.

You'd think an otter would be pretty fearless as an apex predator, but not always.

The cubs are already spending less time close to their mother so it is harder to record them all in the frame at the same time, even though they are only about five months old.  I'll report back on what they get up to next.