News from WeaselCam

It has been a quiet start to the year for my camera box.  The camera has been in place all the time since last March with a peak in weasel activity late last summer.  There was only one brief visit from a male weasel in January this year, one even briefer visit from a female weasel in February and a glimpse of a male stoat that turned round in the entrance in March.  Here they all are in the video - don't blink.  And although the images are blurred, notice the size difference between a male and a female weasel.

A recent paper by Croose et al looked at how well the Mostela (a professional camera box similar to mine) performed in detection of weasels and stoats compared to an external trail camera.  It found that weasels readily entered the box and were detected by both techniques. Stoats were rare and never went inside, which tallies with my experience here.

Non target species have been plenty.  I posted videos of pygmy shrew, common shrew and water shrew in January.  The camera has also seen field vole, wood mouse, American grey squirrel, robin, wren and great tit.  Here is the pygmy shrew - the pipe inner diameter is about 48mm so you can see how tiny the shrew is.

The presence of voles is encouraging as they are the main prey for weasels but the voles only appear in the box at night and the weasels are strictly diurnal. 

Weasel territories are about 1-10 hectares for females and 2-25 hectares for males, while stoats' territories are typically larger, varying from 2-124 hectares for females and 8-256 hectares for males.  That means my patch is as little as 2-5% of a weasel territory and even less for a stoat so it is no surprise that they aren't seen here very often.  I hope when the meadow grows up in the next few weeks the voles may move back in and attract more weasels.  We'll see.

ShrewCam

It seems that shrews are like London buses - you wait ages for one and then three come along all at once.  WeaselCam is mainly seeing wood mice at the moment but a few nights ago there were three shrews.  First a pygmy shrew, which has been appearing from time to time, then a common shrew, which hasn't been common recently, and last a water shrew, the first I have seen since September.

This has happened twice before.  In 2020 I set a camera hoping to find a water vole up near Wark Forest and found three shrew species in one night.  And a few weeks ago I saw three within an hour near Riding Mill.  I don't know if these episodes have just been coincidence or whether the shrews could be following each other around or interacting in some way.  Either way it seems odd.  I posted the video on the Mammal Society Facebook page asking the same question but didn't get a reply, just lots of "likes".  If you have any thoughts please leave a comment.

WeaselCam in December

The camera in the weasel box is there all the time, mostly recording wood mice.  Last month there were five weasel visits, two each from two different animals and the fifth I can't tell.  A male weasel I call weasel 4 was here on the 3rd and the 5th.  The first time he was having a very good look round, probably able to smell the wood mice.

The next time he was dashing about more but I can still manage to identify him on freeze frames. There is a space behind the camera with a few spare bits of wood that he seemed to find very interesting.

The second weasel was a female, the same one who was first here in November.  She also spent a lot of time behind the camera (I have edited most of it out) and it was interesting to see her scent-marking.

She was back a week later for another look round.  I am really hoping she'll stick around and perhaps even move into the weasel wall.

A male weasel dashed in and out so fast on 31st that I can't be sure which it was - my best guess is weasel 4 again.  Otherwise the camera mainly records wood mice, bank voles, the odd American grey squirrel, wrens and great tits.

The voles are interesting.  Almost always I have been seeing bank voles but then this one turned up one night.  It is large with a fairly short tail so it must be a field vole.

One very pleasing visitor was a pygmy shrew who has been in a few times, once in daylight.

I am hoping for many more weasel visits in 2025 and perhaps even a few stoats as well.

End of year favourites - Shrews

WeaselCam has been on tour a few times this year but has failed to record a weasel away from here.  It has, however, been good at recording other small mammals.  While in Williwood, the home of Denise & Phil, the box was visited by three species of shrew within an hour, providing an opportunity to compare their shape, body size and tail length.  From the top they are common shrew, pygmy shrew and water shrew.

Here's the video.

And here are the three individual species - common shrew,

pygmy shrew,

and water shrew.

SardineCam 2

Two of my cameras have been on tour again, this time to Denise and Phil near Riding Mill in South Northumberland.  As before, one camera was set up with a sardine scent lure and the other was in a camera box.  SardineCam was set in woodland edge for the first week and within woodland the second week.  It recorded 1061 videos in all, most of which were of wood mice.  As last time, the mice were fascinated by the sardine smell.  A domestic cat also came by to sniff but the highlight was a roe doe.

Passers-by taking no interest in the sardines were fox, American grey squirrel, robin, blackbird, song thrush and wood pigeon.

The camera box was set at woodland edge in the first week and recorded 546 videos, almost all of wood mice.  In the second week I put it in a rough grass field, still not far from woodland. This time there were only 163 videos and almost all were of shrews - common shrew, pygmy shrew and, most excitingly of all, a water shrew.  There is a small garden pond nearby but the nearest large pond is 160m away across a railway line.  Here are the three shrews in frame grabs from the video to compare their size, body shape and tail length, common shrew above, pygmy shrew middle and water shrew below.

And here is the video.

It was fascinating to find another water shrew away from water, so soon after the one in my garden.  Here is a montage of more water shrew action, all high speed.

If anything the common shrew is even more frantic.  It was interesting to see it collecting the sunflower seeds I had put in.  Shrews are insectivores but water shrews and common shrews both take sunflower seeds in my garden.

The smallest of the three, the pygmy shrew, seems a bit less hyperactive.

We did get a glimpse of a vole but it was very shy and didn't venture past the entrance pipe.  I can't tell what it is with any confidence but from its size I suspect it is a field vole rather than a bank vole.

So no mustelids, which we were hoping for, and no wood mice in the field, but it was great to see all the shrews.  And it is fascinating that moving the camera 50m from woodland to grass completely changes the clientele.  I am not sure it will be worth persevering with the sardine lure but the camera box seems by far the best way to see small mammals.

SardineCam

A couple of my trail cameras have been on tour - to my friends Gill and Martyn in deepest darkest Hexhamshire.  I took a new camera box for one camera and set up the second with a sardine lure as a new experiment.  Sardines are used by researchers to increase detection of carnivores so I wondered if it would work here.  Hexhamshire is home to polecats (Mustela putorius), one if the UK's most elusive mammals, so one aim was to see if we could catch one on camera.  The more realistic aim was to see what we would find.

The cameras were set for three weeks and at the end of that time both SD cards were full.  The sardine camera had 398 videos and the box camera 498 so I had plenty to look through.  The sardine camera was set up at the edge of woodland with the camera and the sardine can fixed to opposite ends of a piece of wood.  The can was secured with a cable tie.

SardineCam recorded 11 species but only four of those were interested in the sardine lure - the others were just passing by.  The four were badger, wood mouse, magpie and domestic cat.  The badger visited only once but tried hard to get into the can.  The camera gave a great close up of its teeth and claws (with a spider in the top left of the lens).

The magpie visited twice and the first time it managed to peck a few fragments of fish, even though the can was only slightly open (the can is now very visible after badger removed all my camouflage).

The wood mouse visited many times, obviously attracted by the smell but not trying to get at the can.  The cat just sniffed a few times and walked on.

Most of the 398 videos were of American grey squirrels.  Other passers by were blackbird, robin, wood pigeon, pheasant, roe deer, and red fox.

My new camera box was set up at the base of a stone wall.

It had large entrance pipes hoping to entice in slightly larger animals but in the end the only visitors were wood mice, bank voles, common shrews and pygmy shrews.  Here is a brief summary of 498 videos (most of which featured a wood mouse!).

It was very interesting to try out the cameras in a new environment.  The card in the  camera box was full in only nine days so another time I would need a bigger card.  I was hoping we might see a stoat or a weasel and I still have polecat on my wish list.

End of year review - Video 3

I made a new small mammal trail camera box last year and I have been using it a lot this year, mainly in the hope of seeing a weasel or a stoat but so far without luck.  From time to time I put a few sunflower seeds in so that it will smell of mice and voles to attract the predators.  The box has seen wood mice, bank voles, field voles, common shrews, pygmy shrews and brown rats, as well as robins, wrens and great tits.  The two mammals I am most pleased with are field voles which come in when the box is in the meadow and pygmy shrews which come in if the box is in the copse.

The pygmy shrew is Britain's smallest mammal and is quite widespread but very hard to see.  In fact I don't think I have ever seen one other than on a trail camera or in a Longworth trap.  It is good to know they are here in the garden even if I don't see them.

SmallMammalCam

This blog has been taken over by insects in the last few weeks so it is high time we had some trail camera images.  My small mammal trail camera box, modelled on a Mostela, has been set in the garden for over a month, hoping to catch a glimpse of a weasel or a stoat.  So far there has been no sign but smaller animals are daily visitors.  I put in a few sunflower hearts from time to time so the box will smell of mice and voles which may, in turn, tempt a curious weasel.

The most frequent visitors, especially in daytime, are bank voles.  They vary in size as some are not full grown.  The video shows a full size vole stuffing its cheeks with seeds before taking them off to eat in peace or to hide for later.

Wood mice are mainly nocturnal and so far have only shown up at night, so in black and white on the video via infrared.  They usually turn up long after the voles have taken all the food.

Common shrews are insectivores but they are surprisingly keen on sunflower hearts, something I have seen before.

Smallest of all are pygmy shrews.  Weighing only 5g or so they are slimmer than common shrews with a proportionately longer tail and with two-tone colouring rather than the three-tone of common shrews.

The last video puts them all together to compare their sizes.

Pop goes the weasel

Ever since the weasel turned up in the garden in the summer I have been trying to get another picture.  Inspired by the Mostela*, a trail camera box used for monitoring stoat and weasel populations, I built one similar from a translucent plastic storage box (£7 from Dunelm).  There are two holes at one end and a trail camera at the other.  The Mostela was designed by Jeroen Mos, an ecologist and small mustelid researcher in The Netherlands, and is an enclosed box with a cutaway plastic pipe connecting the two entrance holes.  Wanting better pictures in a more natural setting, I made mine to admit natural light and built a small "stage set" of bark and loose bark chippings at one end.  The trail camera has a +2 dioptre lens to cope with the close focus.  It can record in colour in daylight but reverts to infrared when the light is poor or at night and it is then augmented by a motion-activated battery-powered infrared security light (a Brlnno APL200).  This is a view of the box with the lid removed.

Here are the camera and the infrared light.

This is the "stage set".

Here is the box in the garden with two Victorian land drain pipes as access tunnels.

Like other small mustelids, weasels are very inquisitive animals and will investigate any small hole which might contain prey.  For the first few days I baited the camera box with sunflower seeds so that it would smell of voles and mice but recently it has been left as it is (although mice and voles still visit every day).  I had the camera box set in my garden and the local nature reserve for four weeks before a weasel eventually made a brief appearance this week.  In fact it was very brief so I have added a 25% slow motion replay to the video.

Several other animals are much more regular visitors.  They include wood mice, always at night and so in black and white.  Wood mice visit every night and spend a lot of time in the box.  There is no food for them but perhaps it is warm and dry and feels safe.

Bank voles more often appear in daylight.  It is a pity the weasel didn't stay this long.

Common shrews also mostly turn up in daylight.  This clip also has a 25% speed replay.

Pygmy shrews appear both in daytime and after dark.

And a couple of very unexpected visitors.  Both birds were in the box for over two minutes and got rather agitated when they couldn't find the way out.

I plan to leave my weasel box set in the hope of more recordings and, perhaps, one day even a visit from a stoat.

* Mos J, Hofmeester TG.  The Mostela: an adjusted camera trapping device as a promising non-invasive tool to study and monitor small mustelids.  Mamm Res. 65, 843-853 (2020). https://doi.org/10.1007/s13364-020-00513-y

ShrewCam

The small mammal trail camera has been regularly recording shrews, along with the dozens of mice and voles, both in my garden and at the local nature reserve.  When I looked closely I realised that there were recordings of pygmy shrews as well as common shrews from both sites.

Compared with a common shrew (Sorex araneus), a pygmy shrew (Sorex minutus) is noticeably smaller; has a significantly longer and hairier tail; has two-tone colouring, lacking the paler flanks of the common shrew; and has a rather domed head and a thin pointed snout.  Some of these features are quite hard to pick out on a video, or even on frame grabs, because shrews move at such high speed.  The body weight of a pygmy shrew is 2.5-7.5g and of a common shrew 6-12g.  In the video I have added a bank vole (14-40g) and a wood mouse (13-27g) for comparison.

One advantage of the small mammal camera box is that the animals are all more or less at the same distance from the camera, making a size comparison easier.

In a still frame from the video, this is a pygmy shrew, showing the long tail in the first image.

This a rather blurred high-speed common shrew but you can see the size difference.

On the same scale this is a bank vole.

And a wood mouse.

CritterCam - the search for a water vole. Part 1

This all began in May, when I was doing my bird count near the Wark Forest for the BTO Breeding Bird Survey.  At one point I glimpsed a small mammal running across the track out of the corner of my eye.  It was dark, vole-shaped and rat-sized so I wondered if it could be a water vole.  There is a very small stream running through a pipe under the track, no more than 300mm in diameter, and because of the dry spring weather there was almost no water flow.  The habitat is poor unimproved wet grassland with mostly rushes rather than grass at that point, not a habitat I associated with water voles.  (I used to see them 50 years ago in a slow-flowing lowland river.)

Although the BTO BBS records mammal sightings I wasn't confident enough to record a water vole.  I did, however, send a message to Kirsty Pollard, a water vole expert at Durham Wildlife Trust and she passed my email on to Kelly Hollings, Northumberland Wildlife Trust's Project Officer in the Restoring Ratty water vole re-introduction project in Kielder.  Kelly was very encouraging and said the habitat was good for water voles, similar to some of the release sites in Kielder, so I went back with three trail cameras in July.  The cameras were in for a week, one close to where I thought I might have seen a water vole and two on a slightly larger but still very small stream (<500mm across) a couple of hundred metres away.  They recorded hundreds of videos and on a first look through I couldn't see much very exciting.  There were lots of glimpses of small mammals and I could identify field voles and wood mice, as well as reed buntings, meadow pipits and a roe deer's ankles.

Before giving up I had another look through the videos and could pick out a few where the voles looked bigger.  They were all on the on the trickle of a stream where I had my first sighting and there was very little on the other cameras.  It is difficult to judge scale although there is a slice of apple visible in the first clip.  I sent a very brief extract to Kelly and she replied that she was 99% sure it was a water vole.

So I went back earlier this month with two cameras and put them both on the first stream.  In most places it is difficult to see any water at all as it runs underneath the vegetation.  I spent time clearing a view and making sure the apples were better positioned.  Between them the cameras recorded almost 700 video clips so it is taking a while to work through them.  The first camera was set up here.

There are plenty of images of voles but I think they are probably all field voles.  Bank voles are 8-11cm long (head and body) with a tail 50% of body length, field voles are 9-11.5cm long with a tail <40% of the body length and water voles are 14-22cm with a tail 60% of the body length.  On the video it wouldn't be easy to tell a field vole from a bank vole or a juvenile water vole without seeing the tail but in some images the tail is clearly visible and is short.  (The other name for a field vole is short-tailed vole.)  The first two voles in the video are small whereas the last one which appears briefly nearer the camera looks larger although it still clearly has a short tail.

I also put a piece of raspberry cane next to the apple, 150mm long to act as a scale but the voles didn't approve of my measuring stick and moved and then removed it.

One very interesting sighting was of three shrews - water shrew, pygmy shrew and common shrew.  You can see that shrews don't eat apple but they are very curious (and very fast).  To find all three species in the same place on the same night was a pleasant surprise.

There are another 390 videos from the second camera so I'll report back soon on those.