Yorkshire Pine Marten Project on Channel 5’s Secret Life of the Forest

Yorkshire’s rare and elusive pine martens have been getting some good airtime of late, most recently on Channel 5’s Secret Life of the Forest.

In this blog, we share some behind the scenes details, as the eagle-eyed may have spotted that the pine marten in some of the Secret Life of the Forest footage has a familiar-looking bib pattern. We’ll also run through the wildlife monitoring tech seen in the episode, as it’s proven vital to capturing evidence of pine martens in Dalby Forest and the North York Moors National Park.

The Yorkshire Pine Marten Project features in series 2, episode 7 of Secret Life of the Forest, available for streaming on Channel 5 here.

Blog by Ed Snell

On September 13th 2022, I met with Maks Swiderek, who was filming the stories of people and wildlife in Dalby Forest, and nearby forests, in the North York Moors National Park. This warm September day was my turn to provide Maks with a tour of our work on the Yorkshire Pine Marten Project.

I took Maks on a typical day of survey work on the Yorkshire Pine Marten Project, which involves checking baited trail camera sites to switch over memory cards, check batteries and make sure the location is well-stocked with snacks. While travelling around the forest we also check pine marten den boxes for signs of use with thermal imaging cameras. If a den box appears warm, we’ll set up a trail camera to find out who’s taken up residence. Our last trail camera footage of a pine marten in Dalby Forest was 8-months prior, so I wasn’t holding out hope for any exciting footage on the day… but I was wrong!

That day we discovered footage of the pine marten that we came to know as Two Dots, based on the two dark patches within his distinctive bib fur pattern. Two Dots first appeared on our trail cameras 13 days prior to filming in Dalby Forest, on August 31st 2022, and he continued to visit our cameras regularly for 6 months, until March 21st 2023. He then disappeared and showed up 5 weeks later at Yorkshire Wildlife Trust’s Spurn National Nature Reserve, an incredible trek that took him 60 miles south of Dalby Forest!

At this stage it’s fair to say that Two Dots is Yorkshire’s most famous pine marten! We learnt a lot about him during his stay in Dalby Forest, including where he liked to den and what he liked to eat (including grey squirrels!). Check out this blog for more info and videos covering his Dalby Forest adventures. Yorkshire Wildlife Trust have also put together an excellent blog, sharing details about his time at Spurn Nature Reserve.

The technology we use to find pine martens

Wildlife watching technology has been key to finding and monitoring Yorkshire’s elusive pine martens. Trail cameras and thermal imaging cameras have enabled us to first detect the species and then continue to monitor them in non-invasive ways, as the last thing we’d want to do is disturb a pine marten sleeping in a cosy den box!

Trail cameras

We use trail cameras in a variety of ways for this project, from responding to public sightings of a marten and setting out a camera, to large-scale surveys of forests, through to monitoring den boxes.

We favour the Browning Recon Force range of trail cameras for this project, as these cameras have excellent battery life and produce clear images for identifying individual martens from their unique bib patterns. They’ve also proven to be robust - in 2018 we purchased 50 Browning Recon Force Advantage trail cameras with part of our Heritage Lottery funding. Many of these cameras have now spent over 1,000 days in the field.

The Browning Recon Force Advantage has now been superseded by the newer and shinier Browning Recon Force Elite HP5, which features sharper images (especially at night), wider FOV, a faster trigger, and compatibility with rechargeable batteries.

Thermal imaging cameras

Thermal imaging cameras are proving to be highly effective for monitoring pine marten den boxes. With a thermal camera, a den box can be monitored from a distance and will show warm patches if an animal is inside. If it looks like the den box is in use, a trail camera can be installed 5 metres from the den box to find out which species has taken up residence and observe behaviours around the box. Note that pine martens are legally protected under Schedule 5 of The Wildlife and Countryside Act 1981. This work should only be carried out by those that have received training to avoid the risk of disturbing a denning pine marten.

In Secret Life of the Forest, I’m using a Pulsar XP50 thermal imaging monocular to check den boxes. This is a slightly older model, recently superseded by the Pulsar Telos XP50. Pulsar thermal imaging cameras have become our go-to for monitoring pine marten den boxes, as the whole range features a good level of thermal sensitivity, which is important for taking a confident reading, and they can record photo and video for our records. Learn more about monitoring pine marten den boxes with thermal imaging cameras here.