Tag Archives: Surrey Mammal Group

I finally see a water shrew

Those of you who have been following my blog for the last 18 months will know that I have not had any success at seeing water shrews, despite numerous attempts.

I had read that the best place to see water shrews was in clean streams and watercress beds (not that they eat watercress, but the insects they so eat need nice clean water, so are often found in watercress beds). So my first attempt was in Hampshire, where they grow lots of watercress. I ended up seeing water voles instead (they’re even rarer, and rather partial to a bit of watercress). Despite returning several times, I never saw a water shrew there (maybe the otters, which I also didn’t see, have eaten all the water shrews).

When I heard that at least one water shrew lived on one of the ponds at Surrey Wildlife Trust’s education centre, I got permission to spend some time standing silent and still by the pond for a few hours. It was a rather meditative experience, but still no sign of the shrew. Undeterred, I tried again a different day. This time I think I got a bit closer, as I heard a squeak that may have been a water shrew, but didn’t get a glimpse.

That approach was also not working very well, so I put my quest for water shrews aside for a while. Imagine my feelings when the reports from the first couple of weeks of harvest mouse trapping featured several water shrews, yet I was unable to attend due to work.

When I finally got out to help with the harvest mouse trapping it was at a couple of sites where no water shrews (or harvest mice) had been found the week of the survey, and my session did nothing to change that record.

Finally, on the third harvest mouse site I helped out with, my luck changed. The first animal we found was a harvest mouse, and not long after I got to see my first water shrew.

A water shrew who's reluctant to come out of its temporary nest in a longworth trap
A water shrew who’s reluctant to come out of its temporary nest in a longworth trap
Water shrew scurrying off after being weighed
Water shrew scurrying off after being weighed

Water shrews are the biggest of the British shrew species, and are usually darker than other shrews, with a silvery underside. I had my hopes raised then dashed a few times at other sites when we happened to catch a common shrew that was darker than normal. But you can really make sure by looking for a fringe of bristles on the back legs and under the base of the tail.

Like all shrews, water shrews are insectivores, and have noses like Wombles. They live life at quite a pace, having a fast metabolism. They’re probably the most striking British shrew, with their dark back and light underside. I didn’t manage to get a good photo, as I didn’t want to disturb the animal more than necessary. You can just see a dark shape disappearing into the foliage.

So, I finally ticked water shrews off my British Animal Challenge list. I wonder what species I will see next…


In search of harvest mice again… and again… and again

For my British Animal Challenge I am trying to see every species of mammal, reptile and amphibian living in the wild. For some that’s been fairly straightforward – a case of going to the right place at the right time. Others have been more elusive. My focus this month has been on two of the trickier subjects: harvest mice and water shrews (more on the latter in my next post).

Harvest mice live up to their scientific name: micromys minutus. They are tiny. As their common name suggests, they like living among crops (grains) or areas of tall, seedbearing grasses. This makes spotting them while out and about unlikely.

Harvest mouse on seedhead

Helping out with some scientific harvest mouse trapping projects was likely to be my best chance to see them. So last autumn I volunteered to help with harvest mouse surveying at Gatwick airport. While it was a fascinating experience, we didn’t find any harvest mice. Undeterred, I volunteered for a session this year at Gatwick (work has been pretty intense lately, so I could only get to one).

Once again I got to drive through 10ft high gates topped with barbed wire, past the intimidating signs saying authorised vehicles only, before leaving the car in the glow of the runway lights, and heading off into the mini wilderness just a few hundred metres from the runway, by the River Mole. I was helping out Gatwick’s resident ecologist, Rachel Bicker (they do a surprising amount of biodiversity work at the airport). Like last year, we didn’t find any harvest mice, although we did have a good crop of voles, shrews and woodmice.

Surrey Mammal Group (working with Surrey Wildlife Trust) have been busy on a new harvest mouse project this autumn. They’re working with geneticists to see if hair samples from harvest mice can tell us about connectivity across the landscape. How related are populations in different sites to each other? Are they isolated by habitat fragmentation, or are they able to disperse and mix? This is important for the resilience of the population. And if harvest mice can move between sites, other animals will be able to as well.

Of course, to test this we first need to get samples from harvest mice. Last year the mammal group did a lot of work surveying various sites for harvest mice, and, while they were at it, tested 3 different trap designs. Based on these findings, they selected the sites with the most harvest mice last year to resurvey this year to get the samples, starting with the most harvest mousey site.

Frustratingly, work commitments meant I couldn’t get along to any of the checks at the first site, and I was ill for the week of the second site. I was restricted to seeing the updates on Facebook. The weeks progressed with plenty of voles and shrews (including my nemesis, the water shrew), but not a single harvest mouse. The dedicated volunteers consoled themselves by collecting mouse, vole and shrew poo for students to analyse for parasites.

I was finally able to help for the last check on the third site. Once again, it was the same story, the harvest mice from last year seemed to have disappeared, leaving only voles, woodmice, shrews. It was an interesting and pleasant way to spend the Friday evening, after a stressful week at work, but did leave me wondering what’s happened to the Surrey harvest mouse population.

The next site I volunteered at was by the River Wey, where I used to walk during my student days. I’d never thought about the wildlife that might live in that meadow, but looking at it now, it seems like ideal habitat for small mammals. The news from Facebook was encouraging – the group had finally caught some harvest mice, and got enough samples to analyse the population at that site, at least. Was it the night I would finally see a harvest mouse in the wild?

Harvest mouse site by the River Wey
Harvest mouse site by the River Wey

There are two moments of suspense in checking the Longworth traps. Firstly looking to see if it’s been triggered, and then, once you’ve opened the trap in a bag, waiting to see what will emerge.

Checking a longworth trap
Checking a longworth trap

We hit gold with the first triggered trap we found that evening: a harvest mouse. They are tiny. And lovely. This particular mouse had already been caught, fur clipped and sampled earlier in the week, so we didn’t need to weigh or take a sample from him again.

A not very good photo of the harvest mouse we found
A not very good photo of the harvest mouse we found

In total we had 10 small mammals in traps that night, but only one harvest mouse. Still, I had finally done it: I had seen one of Britain’s smallest and cutest mammals in the wild for the first time.

The surveys are continuing for another week or two, and hopefully we will get enough samples from other sites to compare. It will be interesting to hear the results from the lab. And hopefully it will help us find out more about habitat connectivity in Surrey. If this approach works it may help other parts of the country monitor their living landscape.

12 ways to find mammals

Finding mammals can often be hard – many of them are small, or nocturnal, or both. Last week I got to hear the great ecologist and mammal expert Pat Morris speak to the Surrey Mammal Group. He gave a fascinating (if somewhat macabre at times) talk about how to find mammals. You’re probably familiar with many of the techniques he spoke about, but there were perhaps a few less well-known approaches.

  1. Look in local newspapers for reports of mammal sightings: Local newspapers are often a good source of information about where unusual wildlife have been spotted. Clippings from papers may also be useful to refer back to in years to come. If you’re interested in getting information about the presence of a particular species in your area, talking to the local rag and getting a story in there asking people to report sightings may be very helpful.
  2. Molehill mapping: One of the problems of many survey techniques is that they may reflect where most of your surveyers are active, rather than where the species is most abundant. One way to check you have good coverage of surveyers is to get data on where molehills can be found. As moles are very widely distributed, any gaps in your map are more likely due to lack of surveying, rather than lack of moles, which tells you where you need to do more work.
  3. Droppings: not the pleasantest way to survey for mammals, but once you get your eye in, you can get a good idea of who is around. Many books are too squeamish to show useful photos of droppings for identification, but the Mammal Society have an excellent fold-out guide to British mammal tracks and signs, including some lovely drawings of droppings. It’s a handy size and laminated, so easy to take with you when you’re out and about.

    Water vole droppings
    Water vole droppings –  a good sign these elusive creatures are around
  4. Trails: look out for paths that go beneath low bushes, or up steep hedgebanks – they may well have been made by wildlife (such as badgers, who tend to follow the same route each time). Smaller mammals sometimes create tunnels in long grass. Spotting these trails can then give you an idea of where to search for other signs, such as hairs, pawprints or droppings.
  5. Pawprints / hoofprints: pawprints are another good way of telling if a species is around. Look in soft mud, or after snow, and you could find a surprising number. Sometimes it’s possible to tell from the pawprints whether the animal was running or walking at the time.
    Deer print
    Fallow(?) deer print

    Hedgehog and mouse pawprints
    Pawprints from the mammal tunnel
  6. Hairs: some mammal hairs (like badgers) are quite distinctive, while others can be differentiated with the help of a microscope. Hair tubes can help to get samples from small mammals, while barbed wire fences are a good place to look for hair from larger creatures.
  7. Food remains: It’s sometimes possible to tell what’s eaten something by the food remains. For example, watervoles cut leaves at a neat angle, and often leave short lengths behind uneaten. It’s also possible to tell whether a nut has been nibbled by dormice, other mice, squirrels or bank voles by how the nut has been opened (I must get round to uploading some pictures of this at some point).

    Plant nibbled by water vole
    Plant nibbled by water vole
  8. Traps: trapping using safe traps (eg. longworth traps) is a good way to tell which small mammals are around. Camera traps can also be handy (it’s how we first found out we had hedgehogs and foxes visiting our garden). Watch a video of visitors to our Mammal tunnel with pawprint tracks and camera trap. Also look out for other things which may attract mammals. For example, mice like to shelter beneath left-over roadworks signs and refugia left out for reptiles.
    More slow worms under a corrugated tin refuge
    More slow worms under a corrugated tin refuge


  9. Nest boxes and tubes: Monitoring artificial nest boxes and tubes is another way of finding mammals. This technique is particularly useful for dormice.
  10. Dead bodies: Looking out for dead bodies along roads or in old-fashioned cattle grids can give you a good idea of what’s around, and can be used to monitor change in prevalence over time. A bit grim, but not as grim as point 12…
  11. Owl pellets: Dissecting owl pellets and identifying the bones is a good way of telling what small mammals are around to be eaten. It’s relatively straight-forward to identify whole skulls, and teeth are useful for distinguishing between small mammal species. But first you have to find your owl pellets, which may be tricky. Local birders may be able to help you with this.
  12. Discarded bottles: [warning – don’t read this if you’re squeamish or eating] back in the days when most milk came in glass bottles, a lot were left lying around in hedges, woods and by roads. These glass bottles are very effective traps for small mammals, as they can squeeze in, but the glass sides and angles mean they can’t get back out. As glass stays around for a long-time, there are still lots of bottles out there, many of which are now full of the remains of small mammals that climbed in and couldn’t get back out. Some bottles may have lots of little skeletons in a foul soup of rotted flesh. If you have the stomach for it, identifying these remains can tell you what’s been around since the bottle was discarded. If nothing else, this should serve as a reminder not to drop litter.

I hope this brief summary of Pat’s excellent talk inspires you to get out and about looking for mammals (or signs or mammals). Do you have any other suggestions for approaches to finding mammals?



Local wildlife groups

One thing I’ve known from the start of my British Animal Challenge is that, to do it, I’m going to need help. While there are some types of animals it’s fairly straightforward to stumble across and identify, others are more complex. For example, bats. There are around 15 different species of bat in the UK, and they’re nocturnal. Even once I find some, I’m going to need expert help identifying which species they are. And with rare animals, I may well need help as to where to find them. Most distribution information in books is at a level that is too general to be that helpful – even if you know a certain species is present in a certain type of habitat in a county, that’s still a lot of area to cover, when the species may only be in very specific sites…

So part of my research has been around finding out who might help me on my quest. I’ve been surprised to find how many different local wildlife groups there are. I’m already a member of Surrey Wildlife Trust, Surrey Mammal Group and Surrey Dormouse Group. I’ve now joined Surrey Amphibians and Reptiles Group, and the form to join Surrey Bat Group is printed off as well. I’m sure there are many other groups I’ve yet to discover.

These local groups all exist to protect the species they are interested in. Their activities include habitat work, advising landowners, carrying out surveys to help research the animals, and educating people about the species. They are generally run by volunteers, and include members with years of experience and great expertise. If you’re interested in wildlife, why not look for a local group who work with the species you’re interested in? You may be surprised by how many there are out there! I’ve learnt lots from volunteering with Surrey Dormouse Group (and not just about dormice!), and I’ve contributed to gathering data that will help us learn more about this threatened species.

Torpid dormouse
Dormouse found during regular monitoring by Surrey Dormouse Group

I hope that over the next few years I’ll learn more about many other animals, and contribute in a small way to their protection.