Monitoring Pine Martens: A Guide to Individual Identification with Camera Traps

Monitoring pine martens with camera traps is a valuable way to gather data that supports their conservation. One key advantage is the ability to identify individual animals from the footage, offering insights into population size, behaviour and movement.

In this article, we’ll explore how to distinguish between individual pine martens and look at some effective methods for capturing camera trap recordings that increase identification success.Trail camera capture of a pine marten 

The Value of Identifying Individuals with Trail Cameras

Historically, traditional capture-mark-recapture techniques involved physically capturing and marking animals for future identification. Modern trail camera surveys offer a non-invasive advancement of this approach, using an animal’s natural markings for identification from camera footage. This method is known as natural mark-resight and is not unique to pine martens. Many other mammals are recognised through their natural markings, such as spot and blotch patterns on grey seals, pigmentation on humpback whale tails, and the distinctive stripe patterns on tigers. 

The ability to identify individual animals offers more detailed data that goes beyond presence or absence surveys. By identifying individual pine martens, we can gather information such as:

• Population size: An estimate of at least the minimum number of individuals present in the survey area.

• Mapping of potential territories: By recording where each individual is seen, we can map parts of their home ranges and identify areas where territories may overlap.

• Track their movement over time: For example, our knowledge of the martens present in the North York Moors allowed us to identify a pine marten that had travelled over 60 miles to Spurn NNR.

• Keep an eye on the health of individuals: Repeated sightings of the same individuals allow monitoring of their physical condition, including any injuries.
  
  

How to Identify Individual Pine Martens

Identifying an animal as a pine marten from camera trap footage is usually relatively straightforward, as long as it can be distinguished from other mustelid species. However, distinguishing between individual pine martens presents a much greater challenge.

Our best chance of success comes from getting a clear view of the pine marten’s bib - a creamy yellow patch of fur on the chin and chest, that often continues down to the tops of the legs.

Distinctive bib markings on PM04 (Yorkshire Pine Marten Pathways Project) matched between B&W and daylight footage.

Each pine marten has a uniquely patterned bib, which acts like a fingerprint, making it possible to tell individuals apart. The edges of the bib may have distinct shapes and patterns, and there may be patches of darker markings amongst the paler fur. By carefully comparing these unique markings across different sightings, you can confirm which individual animal has been recorded.

Tools and techniques for identifying individuals

For a trail camera capture to be useful, the pine marten’s bib markings must be clearly visible. Several techniques can help achieve this.

Baiting: Baits such as eggs and peanut butter are commonly used to attract pine martens into the camera’s field of view. This can be strategically placed in trees and on the ground in the centre of the frame, where the camera’s focus is sharpest, ensuring the best possible image quality. 

Encouraging Optimal Poses: Placing bait higher up or using a specialised setup can encourage pine martens to stretch their heads or stand on their hind legs, to display their bibs for clearer identification.

Feeding Stations

In areas with higher pine marten densities, individual identification becomes more important. A specialised setup, such as a feeding station, can be a more effective approach than simple baiting.

NatureSpy has collaborated with two projects in Scotland where feeding stations were used to attract martens to the area and gather bib images to estimate the minimum number of pine martens in the area. 

Pine marten feeding stations installed in Alladale Wilderness Reserve

T-Sniffer and Jiggler

Conceptualised by researcher Erwin van Maanen, the “T-sniffer” and “jiggler” offer alternative methods to standard feeding stations for conducting presence/absence surveys and identifying individual pine martens.

A ‘jiggler’ is a bait-filled ball suspended on the end of a wire, encouraging a pine marten to reach up and display its bib pattern. These are typically constructed with plastic practice golf balls and filled with bait such as peanut butter. 

The T-sniffer serves the same purpose but offers a sturdier build, constructed with two connected pieces of tubing. When filled with bait, small holes drilled in the top section allow the scent to disperse. 

Pine marten monitoring setups using the Jiggler (L) and T-sniffer (R). Photo credits: John Martin.

These setups allow the distance between the camera and the behaviour of the animal to be controlled in a way that is not usually possible with standard trail camera deployments, so it’s possible to gather clear images of an animal in the centre of the frame more reliably.

Although the methods described above can be highly effective, it's important to remember that some individual martens may avoid baited locations entirely. As a result, those captured on camera aren't necessarily representative of the entire population.

Choosing the Right Camera and Positioning

Camera Choice: Picking the right camera for your monitoring is the first step towards capturing useful footage. The model you select is key to getting clear, identifiable footage of pine martens. High-resolution trail cameras, such as the Recon Force Elite HP5, NatureSpy Helarctos, or Camojojo Trace are great choices as they can capture fine details, including their markings.

Camera Settings: Videos are more effective than photos. A 20-second clip with a quick re-trigger is ideal as it will increase the chance of capturing the animal from multiple angles via still images taken from the video.

Placement: Getting the camera positioning right is just as important. Placing the camera roughly 3 metres from the target location is ideal for getting the pine marten in focus with good clarity. Too close, and the camera risks losing focus; any further, and critical details may be missed. For reliable triggers, ensure that the target location (e.g. a bait dispenser) is in the centre of the frame. 

Spacing: Camera stations are typically spaced at least 1 km apart, as this reflects the lower end of typical pine marten home range sizes. Habitat quality should also be considered. Closer spacing may be necessary in high-quality areas where animals have smaller ranges, while wider spacing can be suitable in lower-quality habitats where individuals range more widely in search of resources.

Timing: It can take a while for a pine marten to find a baited location. Deploy a camera for at least 6 weeks and consider servicing the camera every 2-4 weeks to check the SD card, batteries and replenish bait.

Creating a Catalogue - Taking Useful Stills

Ideally, with some luck, the animal will move in a manner that reveals all sides of its bib within a single video. Still images can then be extracted, capturing the left, centre, and right views to create a complete record of the individual’s markings. If a full view isn’t possible in one clip, images can be gathered from multiple videos, albeit with less certainty that they all belong to the same animal.

Left and right-hand bib stills of PM04 from the Yorkshire Pine Marten Pathways Project.

It is recommended to collect images of a pine marten’s bib across different seasons whenever possible, as the markings can appear noticeably different between the thick winter coat and the sleeker summer fur. Bib patterns may also appear distorted depending on the animal’s position, such as when the pine marten is stretching to climb or turning its head to one side.

Once stills are collected from multiple animals, a full ‘catalogue’ of bibs can be created, serving as a valuable resource for distinguishing individuals within that particular population.

Beyond Bib Patterns: Other Identification Clues

In addition to bib patterns, other characteristics also assist in identification. While these features alone cannot provide a confident ID, they can certainly provide extra clues.

Body Size and Sex: Male pine martens are generally up to a third larger than females (sexual dimorphism), and if you’re lucky, you may see an obvious sign such as testes, which can immediately rule out the females from your catalogue.

PM01 with his distinctive shorter tail (L) and a male pine marten (R) captured as part of the Yorkshire Pine Marten Pathways Project.

Unique Physical Characteristics: Some individuals have distinctive traits that make identifying them easier. The first pine marten captured in the Yorkshire Pine Marten Pathways Project had a shorter tail, likely due to an old injury. This, combined with his bib pattern, makes him instantly recognisable.

Behaviour: Sometimes, behaviour can provide additional hints. Personality quirks, like food preferences or playfulness, can sometimes hint at which marten you’re observing. For instance, some pine martens consistently prefer certain foods, like eggs or peanut butter, while others may ignore these entirely.

From Footage to Conservation Action

Identifying individual pine martens through camera trap footage is a powerful tool for understanding and conserving this elusive species. With thoughtful setup, careful observation, and consistent recording, researchers and conservationists can gain valuable insights that support long-term population monitoring and habitat protection.

Many of the methods described in this article are utilised in the North East Yorkshire Pine Marten Pathways Project; a partnership of Forestry England, NatureSpy and Yorkshire Wildlife Trust. The Pathways Project aims to set the future direction for pine marten recovery in Yorkshire. Learn more about the project here.