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Tuesday, 24 June 2014

A Failed Mission

Having altered the day from our usual late week natural history day out, due to forecasted rain, Nigel Stringer and I went today to the Cilycwm-Rhandirmwyn area. The main aim was to search some upland crags for diurnal moths and other wildlife, with Cwm Merchon, to the NW of Cilycwm being the premier target. I`d botanised in this area in the past, and inspection of the maps showed crags that were likely to hold natural vegetation that was safe from the depredations of sheep.

                    Above: a distant view of the slopes and outcrops at the head of Cwm Merchon.

Unfortunately, I botched up the map reading (!) and we wasted time walking up another cwm - the Gwenlais. We traced back our steps and started the walk up the correct cwm, but it was getting quite hot in the sun and I personally had lost my usual reserves of energy.

We reached this particular field (see photo immediately above), below a brackeny slope where a yellowhammer (now a rare Carmarthenshire bird) was incessantly singing, and decided to turn back as there were no diurnal moths to be found, save two common species of `grass moth`. This south-facing field was flower-rich, with much thyme and I`m certain (along with nearby crags and heather etc) home to some interesting moths. There`ll be clouded buffs on the crags too, I`m sure!

We then decided on an easier `number` and set off for the Nant y Bai lead mines, just north of Rhandirmwyn village (an area very familiar to Sam, with its array of rare lower plants). A feature of this site is the abundance of sea campion, a species understandably more associated with our coastline, though it also grows on the cliffs of Llyn y Fan Fach, and perhaps too on some other crags in the western BBNP.

                               Above: part of the Nantybai site, with sea campion in the foreground.

I suspect that it is this huge population of metal-tolerant sea campion that was the source of the records of marbled coronet at the one-time Rothamsted trap at Ty`r Ysgol, Rhandirmwyn.
I swept the swathes of sea campion and, repeatedly, caught the caterpillars shown in the following photos. They were not found when sweeping other vegetation.

Above: a larger brown larva, with a smaller greenish one to the right, plus seed capsules of sea campion, many of which had entrance/exit holes eaten into them.
Above: another view of one of the smaller green caterpillars. Any opinions as to the identity of the caterpillars will be welcomed.

Not a successful day in terms of moth recording - it just seemed too hot and sunny for them to be on the wing, though several common butterfly species were seen, including a large skipper spotted by Nigel Stringer actually drinking from a stream - everything is so dry and dusty! Keeled skimmer Orthetrum coerulescens dragonflies and the upland bumblebee Bombus monticola seen at Nant y Bai.

Apologies for the lack of moth photos today - there were none to photo, save a few common species. If you want to see some really good moth photographs - and of uncommon or local moths- have a look at the Glamorgan Moth Group website (see link). There`s some superb photos of great moths by Chris Manley,  George Tordoff and others - reward for their moth trapping efforts.


  1. The grown one looks like Tawny Shears, but you'd need to grow it on and/or rear it through to be sure. I wonder if the green one might be a beetle larva? Sorry, suggestions rather than answers!

  2. Thanks for the quick reply Barry. I`ve just looked at Porter`s `Caterpillars of the British Isles` and it does indeed look like a tawny shears caterpillar, though - as you suggest- it`ll need to be grown on.
    Sam - Can you check please, are there any SN74 Rothamsted tawny shears records?
    Have just put out the home traps - too tired for the away-from-home actinics tonight.

  3. There are no accepted Carmarthenshire records of Tawny Shears and only on pended one from SN21 (Glyn Coch Rothamstead, det unknown). The foodplant is plausible and trapping at Nant-y-bai at the right time of year would be amazing.