Blog by Ed Snell – Project Support & Development at NatureSpy
From a wildlife inventory survey to a closer look at pine martens
In summer 2021, we partnered with Alladale Wilderness Reserve to carry out a species inventory survey, capturing images of 56 different species with trail cameras. Species inventory surveys are designed to reveal as many species as possible across the range of habitats in an area. This provides insights into the wildlife activity locally and often encourages further, more specific conservation questions. Following this survey, we decided we wanted to learn more about the pine martens in this area as we saw less pine marten activity than we anticipated.
Pine marten sightings are infrequent at Alladale Wilderness Reserve. Field signs such as scats are uncommon and there’s never been any signs of pine martens using the 6 artificial pine marten den boxes at the Reserve. Our 2021 camera trap survey reflected this with low detection rates of pine martens. We are now collaborating with Mossy Earth to carry out a more targeted survey effort to learn about pine martens at Alladale and on the neighbouring Croick and Amat estates. We’re aiming to gain a better understanding of how many pine martens are in the area and their activity in woodlands across the landscape. This will be informative for pine marten conservation decisions locally and as a baseline to monitor future changes.
Glen Alladale from above
A snapshot of pine marten conservation in Britain
Pine martens were once our second most common carnivore in Britain: they’re now our second rarest. Through a history of persecution and loss of habitat, pine martens have struggled to survive in this country. The species has persisted in isolated populations, with a stronghold in north-west Scotland. Legal protections of pine martens, coupled with conservation efforts over the last 40 years, have seen the species begin its recovery nationally. Natural range expansion of pine martens in Scotland and translocation projects have brought the species back to areas of England, Wales and southern Scotland. It is a pivotal time for pine marten conservation in Britain as conservation efforts support the recovery of this iconic species to its former range.
Pine marten © Tom Broxup
Previous success with pine marten feeding station monitoring
In 2021, we provided camera trap support to a pine marten study in Dumfries and Galloway run by John Martin and Johnny Birks. John and Johnny have both been involved with pine marten recovery in this region of south west Scotland over the last 20+ years. This survey used pine marten feeding stations, designed and made by John, to support the assessment of pine marten population establishment in two of Forestry and Land Scotland’s forests. The approach proved successful, capturing images of pine martens at 7 of the 10 feeding station sites. Designed to be installed out of reach of many other woodland mammals, feeding stations are well targeted towards pine martens: that means foxes, badgers and other animals can’t snaffle all the bait before martens get to it! Additionally, the elevated design means that we can see the unique bib fur patterns of individual martens. With the right freeze frames from the camera trap videos we were able to identify 9 individual pine martens with a good amount of confidence.
Pine marten feeding station
The feeding station enclosure is made from a recycled plastic jerry can, with an entrance cut into one end. The container is attached to a tree branch at around head height with two cords, then wedged sturdily in place with a wooden batten between the container and branch to reduce movement in the wind and when an animal enters. A tray of tasty pine marten snacks is inserted into the container, including eggs, peanuts and dried fruit. To monitor the feeding station, a camera trap is installed on a nearby tree, approximately 7-12ft away, at the same height as the feeding station.
Below: Stills taken from camera trap videos for identifying individual pine martens from their bib fur markings in south west Scotland.
Feeding stations in the Scottish Highlands: The study area
Pine marten home ranges can be extensive, in some cases reaching 30km2 for adult males, and therefore easily crossing boundaries of estates. The Amat Wood is a quintessential Scottish woodland, extending across Alladale, Amat and Croick. This is a relict pinewood and one of the most pristine and contiguous woodlands in the area. It’s designated as a Special Area of Conservation and a Site of Special Scientific Interest and it’s potentially high-quality habitat for pine martens among many other species.
With their varied, omnivorous diet, pine martens will live in a variety of habitats. Woodlands are a core part of their ranges as they provide safe, elevated denning places, but they’ll venture outside of woodlands too when foraging. Their diet contains items such as small mammals, birds, insects and fruit, which can change depending on local resources and seasons. The Amat Wood is potentially great habitat for pine martens, but there are lots of other woodlands in the area too, varying broadly in tree species and ages. Large-scale reforestation work in recent decades has begun the restoration of woodlands to the glens. This survey focuses on the area’s diverse woodlands, ranging from young, reforested areas through to the ancient pinewoods.
A view through ancient pines at Alladale Wilderness Reserve
Survey design
We’ve setup 7 feeding stations of the same design used in south west Scotland across Alladale, Amat and Croick. With a spacing of approximately 2km between stations, we’re able to cover the diversity of woodland habitats across these sites and learn more about pine marten activity in the area. The stations will be in place for a minimum of 4 months and rebaited with fresh food once a month. Monthly rebaiting is essential, because if the bait isn’t eaten within 4 weeks, it’ll likely go mouldy anyway, so the chances of seeing a pine marten visit drops off almost completely without a fresh and reliable food supply.
An added benefit of the feeding station design and choice of bait – particularly peanuts – is the additional chance to monitor red squirrels, which can easily access the stations. Red squirrels were reintroduced into this area in 2013, so this is a great opportunity to gain some insight into their activity and presence too! Red squirrels are savvy to predation by pine martens. Unlike grey squirrels, red squirrels evolved alongside pine martens in the UK and recognise them as a potential predator. The squirrel in the final clip below looks interested in the food but appears to be put off by the scent of previous feeding station visitors.
Choosing a suitable trail camera & settings for monitoring a pine marten feeding station
Pine martens tend to be most active between dusk and dawn, so the main consideration with camera spec should be clear night-time footage. Either low-glow or no-glow LED infrared flashes will work well, there’s no evidence to suggest that pine martens are deterred by the dim red glow of low-glow LEDs. To confidently identify individual pine martens from bib patterns, video capture is useful and recommended over photo, as you can gather multiple stills of the pine marten’s bib from different angles in one video clip.
For this survey, we used Browning Recon Force Advantage camera traps, with the following key settings:
Trail camera field of view is centred on the entrance to the feeding station.
Trail camera view of a pine marten feeding station.
Top tips for an effective trail camera setup for monitoring a pine marten feeding station
Optimal distances: We aimed to setup the camera trap between around 7-12ft away from the feeding station. This means the images will be in focus and the animal won’t be too far away for us to clearly see the unique bib fur pattern. In practice, some setups will often be outside of these distances – this is just an optimal range to aim for clear images and a ballpark guide for most models of camera trap in this scenario.
The right height: To make the install and future checks straight forward, we installed the stations and camera traps around 5-6ft high. This inevitably differs depending on which kind of suitable trees and branches are available to install the feeding station to, but as a general guide, above 5ft should be out of reach of badgers and foxes that will be keen to hoover up the bait.
Good aim: Camera traps are designed to work best at capturing footage of animals on the ground. A camera trap’s sensors typically tend to be most reliably triggered when an animal enters the field of view from the left or right, and when an animal is in the centre of the view – although this can differ across camera models. We’re unlikely to see a pine marten enter the feeding station from the left or right of the field of view, so it’s especially important to aim the camera centrally on the entrance to the feeding station where we’re likely to see most activity. Check out this excellent article for a comparison of how detection zones can differ across camera models.
Setting up a trail camera and pine marten feeding station
This survey will now run until winter 2022, we’ll report back soon with our findings!
Separate to our pine marten work, we’re also supporting a camera trap survey for mountain hares this summer at Alladale Wilderness Reserve.
Learn more about our work with Alladale Wilderness Reserve and Mossy Earth over on our project pages.
