Sunday 10 July 2016

Llyn Fach and Home

On Friday night, at the invitation of the Wildlife Trust, South and West Wales, Martin Bell and I ran my Skinner trap at Llyn Fach SSSI. This is a lovely, if slightly remote, unmodified glacial lake, in the north of the county, just on the Neath Portalbot side of the border with RCT.

This was only the third time it has been trapped; the previous sessions being 28/07/2001 (GMRG field meeting) and 24/07/2014 (G.W. Tordoff, M.E, C. Solman and G Watkeys).
Originally, this session had been planned for late June, but the weather prevented that and it was rescheduled.
Being so high (450m ASL) and as it is in the lee of the highest point in Glamorgan (600m), the weather is the dominant feature, often having its very own.
The evening and post midnight weather was forecast to be overcast but dry; though with a rain bearing front due to arrive from the Atlantic sometime in the early hours. I know from experience, that in those higher spots, the approach of a front often causes cloud to thicken enough for light rain over the high ground, well ahead of the actual front and so it happened on Friday, with the cloud lowering right down to the trap site, accompanied by drizzle soon after the trap was switched on.
We decided to carry on until the character of the rain changed and it got heavier.
It was a damp old night, as we trapped through bouts of drizzle and light rain from 22:05 to 01:55, though the temperature didn't drop below 13.70C. We finally packed up when the rain got heavier and felt more like frontal rain.

In all we recorded 28 species, which wasn't great, but given the weather, the low numbers were understandable. When we got to the forest barrier, a couple of miles away, the roads were fairly dry and as I drove down through the valley, it was clear that the rain we had endured, had indeed been localised to the Rhigos mountain, all along.

Three species seem to be new for the site, those being Map-winged Swift, Smoky Wave and Peach Blossom, but for me, the highlights were Grey Mountain Carpet, Scarce Silver Y, Gold Spot and the numerous Beautiful China-marks.

Grey Mountain Carpet

Scalloped Hookitip

Tawny-barred Angle. f. nigrofulvata

I also ran my GMS trap that night, so having had just two hours sleep, I was back up at five to sort that out.

Amongst the forty-odd species was this superb Broad-bordered Yellow Underwing.

Broad-bordered Yellow Underwing


I also had two of these micros: Limnaecia phragmitella, the larvae of which feed inside the deed heads of Bullrush. The nearest Bullrushes to me are over a mile away, but I get them in the garden, occasionally, nevertheless.


Limnaecia phragmitella


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