Trail cameras – our secret agents in the field

Jack Farge, Project Officer, Scottish Invasive Species Initiative
September 2020

Trail cameras are handy gadgets that we’ve found increasingly useful here at the Scottish Invasive Species Initiative – so handy in fact that we thought we’d like to tell you a bit about how we use them and what they show us.

The cameras are fixed in place and are triggered by motion sensors which makes them useful for collecting footage of elusive animals such as American mink – a non-native invasive species that we are trying to locate and trap – which we otherwise wouldn’t see.  Day or night, rain or shine, our trail cameras are on the job!

Mink mysteries
Our first step in mink monitoring uses a simple, low tech method which can be widely rolled out – the mink raft – this relies on an extensive network of dedicated volunteers to confirm the presence or absence of mink across our project area using these floating rafts. Our fabulous volunteers look after these rafts which consist of a tunnel, with a clay pad inside, to collect the footprints of mink, or any animal, that walks through the tunnel (left image below).  Where the presence of mink is confirmed we place live-capture traps onto the raft (right image below) and see if we can catch the mink – which are then humanely dispatched. Mink are naturally curious and usually check out the tunnels on their own accord but they are also sneaky and wily and occasionally they taunt and deceive us – which is where trail cameras come in.

Capturing video footage of mink can provide an insight into their behaviour and help us identify why – even though we know mink are present – they are not venturing into our traps. The raft/trap unit could be positioned on the wrong riverbank or pointing downstream when it would be better pointing upstream – whatever the issue sometimes the trail camera can help us solve the mystery. 

Click video to watch (on YouTube) or scroll to bottom of article

We also have had to solve the case of the disappearing bait!  We couldn’t work out how bait kept disappearing from inside the trap without the trap being triggered and the door closing! Trail camera to the rescue – it turned out that an otter was sneaking in and having a nice snack on the bait while it held the trap open with its large back!

Click video to watch (on YouTube) or scroll to bottom of article

Snapping Sheep
Trail cameras are also proving really useful at our sheep trial site at Macduff where we are working with a local farmer and the University of Aberdeen to see how best sheep can be used to control Giant hogweed through a managed grazing regime. We’ve installed several cameras around the site which allow us to monitor the sheep’s behaviour, without human influence, by capturing videos of the sheep in grazing action. We are also using trail cameras to gather a visual record of the impact of the sheep by capturing time lapse footage of their grazing progress each day.

Click video to watch (on YouTube) or scroll to bottom of article

What else is out there?
Sometimes it isn’t just mink we find.  One of our mink raft volunteers recently asked to borrow a trail camera after suspecting water voles were in the area. Water voles are one of our most threatened native mammals, largely due to mink predation, so it is great to see if they are making a comeback in areas where we are controlling mink.  We were happy to lend a camera as gaining familiarity with these gadgets is  a great skill for volunteers to learn as well as providing great images for the project.  She didn’t get water voles on film but instead found something even rarer, this amazing footage of a family of Scottish wildcats! (N.B. Later confirmed as hybrid wildcats).

Click video to watch (on YouTube) or scroll to bottom of article

Such footage of our native wildlife is really useful and valuable; it can be important for other conservation projects, we can use it on social media to help raise awareness of our native wildlife and it can help engage people with their local environment.  We’ve also found that when working in schools showing a class of children video footage of an American mink and an otter is not only helpful in explaining the difference between the two species, but also great at grabbing and focussing their attention!

You can watch more wildlife clips on the Wildlife Watcher page on our website or on our YouTube channel.

Give it a go!
If you’ve got your own trail camera or can borrow one and would like to learn more about how and where to set it, check out our helpful hints in the Alien Detectives ‘Caught on Camera’ activity.  If you get some animal footage you’d like us to see and share then get in touch with us at the email address below – we’d love to see what you find!

If you’d like to find out more about our mink control project or are interested in monitoring a mink raft find out more at or contact us on

I like to think this mink knew that is was on camera!
This cheeky otter was stealing all the bait out of the mink trap!
When they get stuck in these ravenous ruminants make short work of giant hogweed.
This footage was really useful for the Scottish Wildcat Action project.

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