Water Voles, Marsh Fritillaries and Harvest Mice

This past month has been particularly pleasant with continually good weather and exciting wildlife in Carmarthenshire.

Starting in early August we had our water vole release at Ffrwd Farm Mire Nature reserve. At Ffrwd there are historical records for water vole at the site, but sadly none for many years. The habitat is ideal for them with several slow flowing ditches, with banksides dense with lush riparian vegetation.

A potential set bank of other water vole releases in the past has been mink predation shortly afterwards, however surveys over previous months have shown no mink activity at Ffrwd. These factors contributed to NRWs decision to pick Ffrwd as the receptor site for over 200 voles, breed from 18 caught last Autumn at Llanelli. It was an exciting day, and help was gladly received form many volunteers, with NRW, Wildlife Trust, and Carmarthenshire Council staff all pitching in. Within hours print marks of the water voles were seen exploring on the clay rafts floating in some of the ditches at Ffrwd.

We completed our annual marsh fritillary larvae web count at Rhos Cefn Bryn. Hopes were high after our butterfly friendly summer, and we weren’t disappointed. We found a total of 24 larvae webs which is the highest count since the mid 90’s. Another good find of the day was a larvae web in a field previously unknown to support this declining butterfly.

Marsh Fritillaries have been previously unrecorded at Carmel National Nature Reserve. Two sightings of adult butterflies on the wing this summer prompted us to do a search for larvae webs. We were keen to find out how the butterflies were using the site; if it was suitable enough habitat or if they were merely passing through. We were delighted to find a larvae web on the reserve, and shall look forward to monitoring in the future to see how they fare.

Also started this month was  monitoring for harvest mouse at several of the reserves with the Vincent Wildlife Trust. Bait pots are being used at Ffrwd, Cors Goch and Rhos Cefn Bryn to try and identify if there are harvest mice present. It is suspected harvest mice numbers have declined since the 1970’s and there are very few records in Wales.

The Vincent Wildlife Trust is hoping to build up a picture of harvest mouse distribution; they have access to a laboratory in Waterford, Ireland who are DNA testing poo found in the bait pots. The mesh surrounding the pots is quite small and only harvest mice and pigmy shrews are tiny enough is gain access. A serendipitous outcome of this study is a greater understanding of pigmy shrew distribution.

Scything course at Ffrwd

Scything course at Ffrwd

The volunteer group has also been getting busy using our new scythes. These new tools are going to be used to help manage the woodland glades and some of the grassland at Carmel. We have so far used them on bracken and bramble. They are proving to be an efficient way of working, less noisy and more pleasant to use than our petrol fuelled brushcutters. It’s a welcome relief to be able to hear bird song, sustain a conversation and get the job done effectively.

The ponds at Cors Goch have been cleared out of vegetation. The western bog has approximately 90 ponds, these are all very vegetated with a carpet of sphagnum moss and often purple moor grass, deer grass or cotton grass growing out of it. This is a fantastic habitat for many things, including carnivorous Sundew.

Unfortunately the lack of open water is reducing the bogs appeal to dragonflies and damselflies, of particular concern were the small red damselfly and black darter.

Opening up ponds at Cors Goch

Opening up ponds at Cors Goch

We’ve opened up several of these ponds so that the odonata can lay their eggs in the water, and allow easy access for the larvae to climb out and metamorphosis into their adult form. The open water will also be a bonus to other species, not least lesser bladderwort. Another carnivorous specialist, bladderworts are a genus of aquatic plants, one of which has been found in the ponds at Cors Goch.