When you go for a walk in the countryside, you’re likely to take it for granted that you’ll see birds flitting around; but how often do you see small mammals? Voles and shrews are very elusive and hard to find – despite the fact that kestrels and owls dine on them daily! – so actually seeing one is a rarity.
So, if you want to find out about mammals, how do you do it? It turns out that mammal spotters are very reliant on field signs, such as nests, hair caught on barbed wire, and, er, poo.
Yep, poo. That’s one of the realities of studying mammals! On the Mammal Society’s Facebook page, there are regular postings of interesting-looking droppings… for example, one image yesterday, which could have been either pine marten or fox, drew the comment, “It would need either a sniff test (sweet smelling = pine marten usually) or DNA analysis at Waterford.” The sniff test is what you think it is…
The Mammal Society has been running a survey called “Mini Mammal Monitoring“, aimed at detecting the smallest and most elusive species. It operates on a simple principle: swapping food for droppings. You leave some food in a set of small tube for a few days; they come in, guzzle the food, and leave their droppings behind; you then collect the droppings from the tubes.
What happens next is the clever bit. A few years ago I took part in the Mammal Society’s water shrew survey. Once the droppings were collected, they were sent away and analysed one by one: if there were the remains of aquatic insects in a dropping, then they could be fairly sure that the culprit was a water shrew. Now, the droppings are sent for DNA analysis in Waterford, which means the basic technique of collecting droppings can be used for a much wider range of critters.
Last autumn, I decided to do this at the Knapp and Papermill near Alfrick Pound, a beautiful nature reserve operated by the Worcestershire Wildlife Trust. I left one set of the bait tubes by Leigh Brook, and another set in Tor Coppice. After leaving them for a couple of weeks, I collected the droppings from them, and mailed them off to Waterford for analysis – and waited for the results.
Last week the results arrived back. The Leigh Brook site was the most interesting, with droppings from field vole, wood mouse, common shrew and water shrew. I was particularly pleased to have detected the water shrew again – and when I told the Wildlife Trust, they were delighted as well, because it is a first detection of the species in the reserve. The results will have increased usefulness as part of the wider national survey, particularly when repeated over several years.
So if you ever see me collecting poo, it’s not weird, it’s science! 🙂