Trail cameras

There is a lot of wildlife on Ardnamurchan. It is one of the reasons I returned here time and again … and came back more permanently in 2018.

Some of the wildlife is obvious.

The never-ending parties of tits, siskins and finches on the bird feeders.

A white tailed eagle effortlessly gliding along the scarp slope of Beinn Bhuidhe.

The stag ghosting away in your peripheral vision as you drive back late along the B8007. Did you really see it at all?

An otter rolling amongst the bladder wrack exposed at low tide as it searches for crabs.

But most of the wildlife you never see because it is about when you’re not.

Either the wildlife makes itself scarce when we’re blundering about … or because it’s the middle of the night.

Smile, you’re on candid camera

But with a bit of technology, some patience, a bit of trial and error and a little luck you can see what you’re missing.

Trail cameras (also know as trailcams or camera traps) are movement-activated cameras that record still images or short videos any time of the day or night. During daylight hours they record colour images. At night they use infra-red LED lighting and record in black and white.

I’m using camera traps to detect the wildlife I don’t see because I’m chainsawing out the rhododendron and making a mighty ruckus.

And I’m using them in the vain hope that they’ll help identify the gaps the undesirable wildlife get through to eat the native flowers and trees I’m planting in the newly rhododendron-free areas 😞 .

Red deer hind scouting out a rhododendron-cleared area for newly planted trees

There are dozens of makes to choose from at prices ranging from £25 to at least 20 times that, depending upon the features required. The more expensive models have 4G or wifi built in (and I’ve no experience of these).

Optically - at least from the technical specifications provided by the manufacturers - trail cameras above £150-175 don’t improve very much. Less expensive models tend to offer lower resolution and longer trigger times (I’ll discuss the significance of both of these shortly).

It’s worth noting that none of these ‘hobbyist’ camera traps are going to produce stills or video to compete with the sort of stuff you see on Seven planets, One world ¹.

However, they can produce perfectly acceptable results.

Roe deer buck

I’ve used the Browning Recon Force Advantage and Browning Spec Ops Advantage cameras.

Yes … the names are totally ridiculous ;)

I felt like I should spend the weekends disguised as a bush, or at least be wearing a camouflage hat and jacket, when I ordered them over the phone ².

Resolution

Both these trail camera models deliver still images of 4 - 20 MP (megapixels).

This is nothing like as good as it sounds I’m afraid. This is because the larger images are interpolated when they’re scaled up - effectively adding pixels as the image is expanded.

I’ve only tested the still camera function during daylight and can see no significant quality differences between 4 MP and much larger images.

Do not expect images comparable to your digital SLR … they’re not even vaguely close.

Video is better being up to 60fps 1920 x 1080p HD ³. This is perfectly acceptable and I usually use them at 30fps to save SD card space.

Less expensive models usually offer lower video resolution and/or a lower frame rate. Both reduce the quality of the resulting video, though perhaps not so much it actually matters.

Lights, camera, action

Well, lights, battery life and action.

To work at night the camera needs to illuminate whatever it has picked up using the motion-sensitive sensor. It does this using infra-red LEDs. The two cameras (embarrassingly) named above use different types of LEDs.

The Recon Force Advantage has ’low glow’ IR LEDs. These are visible to the human eye and they are certainly visible to animals (as I regularly capture video of them reacting adversely to the light).

Badger - note the surprise when this poorly-sighted fellow sees the ’low-glow’ LEDs

The Spec Ops Advantage has ’no glow’ IR LEDs. These are essentially invisible to humans ⁴, but are effective over a shorter range (~70% the distance of the low glow LEDs).

The other significant feature to look for in a trail camera is the trigger speed i.e. the time it takes from detecting motion to capturing video (or a still  image).

0.4 seconds might not sound very long, but a small animal - like a stoat - moving fast across the field of view will feature for a further half second on the video before you get 10 - 20 seconds of just herbage waving in the breeze.

Mouse … one of several hundred I have videos of 😞

Both cameras use eight AA batteries. Unfortunately, not just any old AA batteries. You are strongly recommended to use lithium AA batteries which are appreciably more expensive ⁵.

Why lithium? You need batteries capable of delivering high current - at least 2500mAh - and they often need to work at low temperatures. Standard rechargeables or Duracell simply cannot do this.

I get 9-12 months use out of a set of lithium batteries in a well-placed camera (i.e. not too many false triggering events) set to take short videos, about 50% of which are recorded at night. So, although the batteries are not inexpensive, they also last well.

I’m also dabbling with building a solar-powered rechargeable battery pack, though this will only be suitable for areas which receive full sunlight at least some of the time. It will make it less portable, but might be worthwhile for a really good location (or a very remote one).

Irrespective of the technical details of the camera trap, the biggest influence I’ve seen on actually capturing useful and usable images is due to the positioning of the camera.

Location, location, location

Firstly, things to avoid …

• Glare from the sun. Try and position the camera facing north. Or at least somewhere in the arc between north-east and north-west. Not an issue at night of course, but why compromise daytime images beings spoilt by glare and dazzle? ⁶

• Herbage moving close to the lens. This will repeatedly trigger the camera during windy weather. There’s only one thing less interesting than screening 89 short videos containing the same small branch being blown intermittently in and out of the field of view.
• Mounting the camera on something that moves. This almost always ensures lots of false triggering. Even 8-10" tree trunks sway perceptibly in strong wind. A fencepost is good, as is a tree-stump ⁷.

• Mice. This is what’s less interesting. That infuriating branch I just mentioned is insignificant when compared with a couple of hundred ten second videos of mice scurrying around in the foreground 😞

Red deer stag and glare from poorly positioned camera

Obvious places to try …

• Game trails. Large animals usually leave a track or trail, particularly if the ground is soft. I usually point the camera along the trail to get a head-on (or tail-on!) video, rather than a fleeting glimpse as they cross the field of view.
• Paths. Many animals will follow man-made tracks rather than making their own way through the undergrowth. This is where I’ve had most success in filming a wide range of wildlife - from badgers to woodcock.

Roe deer hind on manmade ‘path’ hacked through the bracken

• Bait. I’ve not tried this but you’ll see many camera traps set up pointing at bait of some sort. Some people use an egg, others use cat food or - for pine martens - a digestive biscuit with jam.
• A waterhole. Don’t expect hippos and gazelle, but you might well get an otter or animals coming to drink. I don’t have anywhere really suitable so can’t comment on how effective this is.

The camera should almost always be mounted 30-60cm above the ground. Most trail cameras have a small screen you can use to check the positioning. If the camera is only 30cm from the ground this can be tricky to view ⁸.

Try to position the camera vertical and avoid too much sky in the field of view. The former makes the resulting videos/photos look a bit better quality and the latter avoids lots of ‘blown out’ highlights in the images.

The great thing about these cameras is they’re pretty much ‘set and forget’. You can leave them for a week or a month. You certainly don’t need to check them on a daily basis. They just sit there, quietly grabbing images when triggered.

SD cards

All of the images are recorded onto full-size SD cards. I only use 16 or 32 Gb cards and have only ever run out of space when I setup the camera incorrectly and recorded very long video clips.

With 16 or 32 Gb SD cards now costing only £6-8 it’s easy to carry spares and swap them with the SD card in the camera. I’ve also built a portable, battery powered, Raspberry Pi Zero backup device which copies the card in situ. However, this gets press-ganged into other roles and, frankly, it’s faster to just swap cards over.

Absence of evidence is not evidence of absence

The two most obvious signs that badgers are in an area are their extensive latrines and their corpses at the side of the road. The badger (above) was the first I’d seen on Ardnamurchan and I had no reason to suspect they were there.

The camera never lies.

Pine marten, Ardnamurchan, May 2018

In contrast, it’s not uncommon to see pine martens lolloping across the road and their scats (faeces) are often left in prominent places ⁹.

Of course, the ‘biggy’ in terms of mammals on Ardnamurchan, is the Scottish wildcat. Although this area was designated as a wildcat ‘haven’ about 5 years ago, things have gone a little quiet since then.

Scottish Wildcat Action are now concentrating on Morvern which, although not far away, is across Loch Sunart and likely forms an isolated population.

Nevertheless, over the next year or so I’ll continue to leave at least one or two trail cameras well away from areas of human disturbance in the hope of capturing one on video.