Dormice and Small Mammals


The main purpose of our survey was to see if we could find any Water Shrews. The fact that we have found Water Shrew in Stowey Reserve twice in 5 years, less than 250 metres away as the crow flies, makes us think that there is a good chance of finding them in both reserves.

We concentrated most of our traps, 35, along the bank of the rhyne on the north east boundary of the field. The rhynes on the other boundaries were cleaned out this year and are providing very little cover this spring. The other 14 traps were spread equally across the reserve.  The traps were put in position on the Friday evening and checked on both Saturday and Sunday, morning and evening before being collected on Monday morning.

We caught 8 Bank Voles, 3 were caught more than once. We caught no Shrews or Field Voles although there was an abundance of field signs of vole activity. Field Voles are known to be ‘trap shy’ so it is no surprise that we did not catch any. It was disappointing not to catch any shrews at all although it does not mean that they are not there.

It is worth remembering that Stowey is the reserve that we have surveyed the most often and we have only caught 2 Water Shrews with a 5 year interval between them. We will monitor the level of cover on the banks of the rhynes in Kenn Moor after the cattle have completed the annual grazing and if suitable will repeat this exercise in the autumn when it is normal for small mammal numbers to be higher.

Richard Croucher

Stowey Small Mammal Survey April 2014.

On the evening of  Thursday 3rd April we set out 40 Longworth Traps and 10 Tube Traps in Stowey reserve, Yatton.  The 40 Longworths were placed along the field boundaries of both fields and the 10 Tube Traps were placed across the middle of Westmead.  

The traps were checked on Friday 4th and Saturday 5th AM and PM. They were checked and taken in on Sunday morning. On the Saturday and Sunday members were invited to join us. We had a good turnout including our youngest ‘trapper’ so far, Noah aged 8.  We had a total of 53 live captures. Using fur clipping to mark the animals we were able to be certain that we caught 40 different individuals. We caught 25 Common Shrews, 11 Woodmice, 3 Bank Voles and 1 Water Shrew. This was the first Water Shrew caught during our group sessions but there is one previous record of a Water Shrew in the same area of Stowey reserve.  This was the first time that we weighed each animal. The average weights were Common Shrews  9g,  Woodmice 21g and Bank Voles 24.5g.  The Water Shrew weighed 11g which is at the lower end of the weight expected.

Significantly we were still catching new animals on the final morning which indicates that we had not caught all that were there and that we could have gained more information if we had continued for a longer period. Surprisingly we caught no Field Voles although there are plenty of field signs such as Vole runs and food stores.

The number of animals caught were 4 times greater than in April 2013 which is very encouraging news for our Barn Owls and Kestrels and we did find new Owl pellets under the Owl box.

Richard Croucher

Harvest Mouse Nests Report 22nd November 2013

On Friday the 22nd of November I was joined by Irene, Sue and Geoff to spend a morning looking for Harvest Mouse nests. This is probably the least intrusive method of monitoring for the presence of Harvest Mice as we can be confident that at this time of year they are no longer using the nests.

We started our search on the Strawberry Line between the mosaic seat and the wooden bridge. Here we found one nest in very good condition. This is the third consecutive year that we have found at least one nest in this area.

We then moved on to Footmead, starting behind the owl box. Here we soon found a nest close to where the trail camera caught a picture of a mouse in the summer. Another nest was found in tall grass out in the middle of the field in front of the owl box and at least two more nearer to the field gate. This is very encouraging as it is only three years that the reeds and grasses have been allowed to grow tall enough to create suitable habitat proving the harvest Mouses ability to colonise new areas.

Finally we drove to Littlewood where in some of the clearings there is tall grass and brambles, ideal habitat for the Harvest Mouse. Unfortunately but not surprisingly we did not find any nests in the wood. of course this does not prove that there are none there, only that we did not find them.









If anyone would like to be shown the how and where to search for nests please contact me on and I will be happy to repeat this exercise.  Richard Croucher


Small Mammal Survey at Littlewood 19th-21st October 2013

On Friday the 18th October 40 Longworth Traps and 10 Tube traps were placed along the length of Littlewood reserve either side of the path running through the east side of the wood. The traps were each checked 5 times, twice on Saturday, twice on Sunday and on Monday morning when they were collected.
We had a total of 55 catches which is about half the number compared with a similar survey in October 2012. This time we fur marked all of the mammals caught so can confidently say that we caught 41 different Woodmice, 1 Bank Vole and 1 Field Vole.
This continues the trend we have found in surveys of other YACWAG reserves this year where Vole numbers are significantly down, 12 Bank Voles in Littlewood last year, although this was the first time that we have recorded a Field Vole in the wood. Woodmouse numbers caught were higher than last year but this year we failed to catch any Shrews. Last October we caught both Common and Pygmy Shrews in the wood.
If size alone is a good indication then it would seem that a large number of the mice were juveniles. Before we start surveying next year I will be looking into the value of recording weights of small mammals and whether this will give us an indication of the health and age of the population.    Richard Croucher

Small Mammal Survey 10 Acres, Congresbury Moor 17-18 August 2013

We used 40 longworth traps  and our 10 new tube traps around the edge of the east section of 10 acres starting close to the gate and going around the field in a clockwise direction. Next to every fourth longworth we put a tube trap in the hope that we could start to make some comparisons of their effectiveness. We checked the traps 4 times over 2 days.
Unfortunately we only caught 3 mammals. On Saturday morning we caught a Common Shrew and a Harvest Mouse.  The lack of Voles is probably still a result of the weather over the last 18 months but also a result of the level of grazing in that field last summer.









Also I used the trail camera in Footmead over 2 nights. I now have some videos of Voles trying to access the bait station designed to attract harvest mice and at least 1 clear video of a harvest mouse. I am still working on getting the best out of the camera and have started to wonder how best to share the videos. I have seen that some people/groups open a channel on youtube so that anyone can access.  We are looking into this.  Richard Croucher

Small Mammal Survey at Stowey Reserve 13-14 September 2013

From 13th to 15th of September we returned to Stowey reserve for a second Small Mammal survey this year. We returned to Stowey to get an idea of the effect of the grazing pattern and to see how well the populations were recovering from last years extreme weather.
Since the last survey the centres of the fields have been grazed but the field boundaries were protected with electric fencing. We placed the traps in 4 transects, along the NW and NE edges of Middlemead and along the SW and NW edges of Westmead. As usual we used 40 Longworth traps and as in our recent 10 acre survey we placed 1 new tube trap next to each Longworth. We checked the traps 5 times from Friday morning to Sunday morning. On Saturday evening we moved the 10 tube traps to a line through the middle of Middlemead having found some evidence of vole runs there.
We had a total of 20 catches from 250 trap checks. After taking into account recaptures we had a total of 13 mammals. We caught 7 Pygmy Shrews, 4 Field Voles, 3 Woodmice and 1 Bank Vole. This compares with 10 mammals from 160 trap checks in the spring.
Once again the NW of Westmead was where we had the most catches. We caught all of the Voles along the NE of Middlemead and the SW of Westmead, either side of the ditch dividing the fields. These 2 transects have more rough grass and less sedge and scrub. When we moved the tube traps to the middle of Middlemead we caught no mammals.
4 of our catches were in the new 10 new Tube traps, 16 catches were in the Longworths. This is exactly the same ratio leading me towards the assumption that the mammals have no preference. On one occasion we caught 2 Shrews in the 2 side by side traps. This shows that single lines of 10 traps give an indication of presence but not an accurate population count.
Overall it was encouraging to find both Field and Bank Voles which have been absent in some surveys this year. Also worth noting is the success that we are starting to have using the trail camera with the bait station, those using the YACWAG facebook page will have seen this and on our last visit to Stowey we did find spraint of some kind on one of the cattle drinking points. No firm opinion yet on whether it is Otter.

Hedgehog Tunnel – not just for hedgehogs! June 2013

Deep in a Yatton garden some things stirred!

First it was the badger  Badger Video

Then the cat  

Then the wood mouse Wood Mouse Video 

And finally the hedgehog (hurrah) Hedgehog Video

Monitoring Harvest Mice 1st June 2013

Here is a report from Richard Croucher about his efforts to monitor harvest mice:-

While doing some online research recently I found this link which has a report and short video on a survey being carried out on a nature reserve in Wales. It shows a camera trap being used beside a bait station to record the presence of Harvest Mice.
I was interested to find out what bait was used and what size wire mesh was used to keep out larger mammals (Woodmice and Voles) and birds. I used the email address on the report to ask these questions and have now made myself a bait station which I placed close to the ditch along the Strawberry Line where we have previously found Harvest Mouse Nests. I left the bait station out for 5 nights in varied weather conditions. On retrieving it I found that something has been feeding on both the sunflower seeds and the peanuts that were used.
Without the use of a camera trap I cannot be certain that it was Harvest Mice taking the bait, but if I trust the information that I was given then I can be fairly sure. I will put the bait station  in other places where I have previously found Harvest Mouse Nests and hope to survey the Strawberry Line by moving it along the line at 100 metre intervals from Yatton station to the wooden bridge near the A370.

Small Mammal Survey at Footmead 17th/18th May 2013

The traps were set out on the evening of Friday 17th May. All 40 traps were used in 4 transects of 10 traps each. Transect A started inside the field gate and followed the southwest ditch about 5 metres from the ditch on the border of the rough grass headland and the previously cut area ending behind the Owl Box. Transect B started in the south east corner and followed the east hedge, under the hedge. Transect C followed the ditch around the north east corner, very close to the ditch. Transect D started near the field gate and followed eastwards across the middle of the field.
The traps were checked 4 times each, on Saturday and Sunday AM and PM. On the first check we found no mammals. The following 3 checks resulted in 7 live catches, all Common Shrews, no Voles or Mice.  All 7 catches were in Transects A and C. We were able to fur clip some of them and others had distinguishing marks so we can be confident that we had 2 recaptures. That means that we caught 5 different Shrews over the 2 days.    Richard Croucher

Dormouse Survey 20 April 2013

Dormouse nest boxes and tubes were installed on Cadbury Hill on 20 April by a group of members led by Sarah Dale.  They were lucky enough to hear a cuckoo while on the Hill.

The next boxes and tubes will be checked to see if they have been used on 13 July, 21 September and 9 November (all Saturdays) from 2-4pm.