The who’s who of poo (Warning: may contain traces of poo)

Now that you are familiar with mustelids, and hopefully whizzed through a brief history of nearly everything pine marten in our previous blogs, its time to get down to the exciting stuff…poo.

Biology of scats…

Marten poo, like that of many carnivores, is known as scat and is one of the easiest ways to know that you have martens in town (1).  As well as being a necessary biological function, martens also use scats to communicate between each other and other species. Martens are strictly territorial and won’t tolerate another animal of the same sex on their patch. But they do also like to avoid conflict where possible, so by laying scats throughout their territory they can clearly mark it to any passing martens that this seat is taken. Their strong-smelling anal secretions can give a clear message to other martens about their sex, condition and reproductive state (2).

Marten scat is very distinctive and, if you know what you’re looking for, is easy to tell apart from other mammals in the area. Its main descriptor is that they are a dark, coiled, continuous squiggle that is generally 10-13 mm wide and 80-120mm long (3). Mustelids have a different digestive system and gut to many other carnivores and this creates a very mucousy scat that tends to stay in one long piece, as opposed to canid scat that generally breaks up. The most freshly deposited scats are known as ‘Moist Classics’ and are dark, long, slim and slimy and tend to contain lots of small mammal remains (Picture 1).  If a marten has been eating lots of eggs the scats become much lighter and softer (Picture 2), a late summer scat will be filled with berries and can look lumpy and purple, and, of course, anywhere where people are baiting to encourage the martens their scats are often filled with peanut pieces (Picture 3) .


The best way I’ve found to truly distinguish it from fox (the most commonly confused scat) is to use its scent to guide you. The ‘not-unpleasant’ sweet-musky smell from a fresh scat is unmistakable and whilst people disagree on exactly what to equate it too (everything from Parma violets, to Lapsang Souchong tea), there seems to be universal agreement that it should not make you gag (3). Unlike, of course, the acrid stink of a freshly rolled in fox scat, that is all too familiar to dog owners everywhere. In recent years many ‘conservation dogs’ are being trained up to sniff out the scat or dens of rare or shy species. Even your untrained pet dog can be a real asset for finding marten scat as it is such a novel scent that is unique and causes most dogs to get very excited. So take a peek where your pooch is perusing you never know what they might have found!

4. Surveying for scats

4. Surveying for scats

Take a wander through the woods…

Mammalogists have a bit of a reputation for our obsession with poo, but its hard not to get excited by the fresh glisten of a recently dropped scat that shows your target species has passed by recently! Martens, like most mammals, are rarely seen and it is nigh on impossible to survey the population by sightings alone (4). Pine martens despite being a shy, elusive, and cryptic creature are actually real exhibitionists about their scat. They don’t build latrines like badgers and polecats but instead like to deposit it in prominent places; tree stumps, the top of denboxes, and in the middle of footpaths and tracks (5).

5. Scat on a denbox

5. Scat on a denbox

This brazen pooing is very handy to us scientists as it makes surveying for martens very simple! In pairs we walk transects along short sections of forest track throughout the area and examine any scat we come across. It’s rare to find anything but fox, marten, or dog on the forest tracks, but working in the Dean yielded lots of exciting boar droppings scattered across the tracks too.

It can get tricky to only pick up marten scat though, as once the scats have been deposited for a while they can lose some of their signature odour, and foxes are not adverse to snaffling blackberries and bilberries in the summer which can mask the foul odour of their normal scats. To add extra confusion foxes also overmark martens and vice versa, so you can come to a great pile of scat in the track that is multiple fox and marten scats laid atop one another. Martens and foxes are intraguild competitors who fight for the same prey sources but as they both try and avoid conflict where possible they transfer their battle to the forest tracks and use scat to make their point.

Building a scatalogue…

Collecting the scat helps us build a fuller picture of how our martens are expanding and using the landscape. It is important though not to equate number of scats found to number of martens in the area, no clear relationship exists, and nobody is quite sure why some areas become scat havens and some are barren despite marten presence confirmed by camera trap (6). Some martens just like to scat a lot, and some do not, it’s a personal choice!

Scats can tell us all sorts about what a marten has been eating too (7). Hard part analysis (breaking up the scat and looking at the contents either by eye or under microscope) can yield lots of small mammal bones and jaws (vole teeth being particularly obvious; Picture 6 &7), mammal fur, feather quills, and of course the late summer delicacy; berries of all kinds!

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(1) Birks, J., Messenger, J., Braithwaite, T., Davison, A., Brookes, R., Strachan, C., 2004. Martens and Fishers (Martes) in Human-altered Environments. Springer-Verlag New York

(2) Hutchings, M.R. and White, P.C., 2000. Mustelid scent‐marking in managed ecosystems: implications for population management. Mammal Review 30(3‐4).

(3) Birks, J. 2017. Pine Martens. Whittet Books Ltd, Essex, UK.

(4) Kubasiewicz, L.M., Quine, C.P., Summers, R.W., Coope, R., Cotterell, J.E., A’Hara, S.W., Park, K.J., 2017. Non-invasive genotyping and spatial mark-recapture methods to estimate European pine marten density in forested landscapes. Italian Journal of mammalogy, 28(2), pp.265-271.

(5) Birks, J., Messenger, J., Halliwell, E., 2005. Diversity of den sites used by pine martens Martes Martes: a response to the scarcity of arboreal cavities? Mammal Review, 35(3&4), pp.313-320.

(6) Cavallini, P., 1994. Faeces count as an index of fox abundance. Acta theriologica, 39(4), pp.417-424.

(7) Caryl, F.M., Raynor, R., Quine, C.P., Park, K.J., 2012. The seasonal diet of British pine marten determined from genetically identified scats. Journal of Zoology, 288 (4), pp.252-259

(8) Jordan, N.R., Messenger, J., Turner, P., Croose, E., Birks, J. and O’Reilly, C., 2012. Molecular comparison of historical and contemporary pine marten (Martes martes) populations in the British Isles: evidence of differing origins and fates, and implications for conservation management. Conservation Genetics, 13(5), pp.1195-1212.