AFC Field Meeting, Knockan to Loch Urigill, 23rd July 2017
Six members of the Field Club were joined by two visitors from Staffordshire and Gwen’s collie Jess for an expedition to the western shores of Loch Urigill on Sunday 23rd July. We had intended to reach the loch by working our way up Na Luirgean, which drains it into the Ledmore River, but a recce earlier in the week encountered some seriously ‘haggy’ ground, so the route was changed to start at the large lay-by in Knockan (NC211105) at 1045 hrs.
After leaving the old road, we took the track dropping down to the south side of the Abhainn a’Chnocain, with a ‘running workshop’ on the wide variety of grasses, sedges and rushes found along its edges. We also came across dried-up puddles in the track containing very curious clusters, up to 10cm tall, of dark, fibrous structures; these were the silk and mud tubes of the larvae of midges Chironomus sp., normally submerged.
Progress slowed as we encountered the limestone, with outcrops covered with the white-felted leaves of mountain avens Dryas octapetala, with a few late flowers. These outcrops are often surrounded by or capped with acid, peaty soils, so that different plant communities are closely juxtaposed in a delightful micro-mosaic. Such areas provide suitable habitats for a variety of eyebrights Euphrasia spp., the identification of which is, regrettably, a matter for the specialist. Damper areas had the tiny shoots of lesser clubmoss Selaginella selaginoides, which become a conspicuous peachy colour as they age. Adjacent limestone flushes hosted large clumps of yellow saxifrage Saxifraga aizoides, and there were occasional white-flowered heads of northern bedstraw Galium boreale along the path.
After negotiating a really awkward stile crossing a fence above the gorge, we dropped down to an island in the course of the river (NC223103) to look for a puzzling horsetail which had been found there a year earlier. We located a good stand and on close examination it proved to be Mackay’s horsetail Equisetum x trachyodon, a very rare hybrid between rough and variegated horsetails, which is known from one other site in Assynt and only five in Scotland as a whole. Persistent very fine teeth which extend upwards from the black sheaths ringing the stems are a distinctive feature of this hybrid.
Fording the river, we then made our way eastwards up a narrow tributary burn running through peaty ground. The grassland along its banks was ‘pepper-potted’ with the conspicuous, mostly vertical, burrows of an active water vole colony, which extended over nearly half a kilometre. Collections of burrows were noted at some eight locations, with apparently unoccupied areas of bank in between, and there were occasional aggregations of dung, which apparently act as markers for a series of separate territories occupied by breeding females.
We lunched on a limestone outcrop above the burn (NC225103) in a pleasant breeze. The short turf on the outcrop was studded with plants of alpine bistort Persicaria vivipara and alpine meadow-rue Thalictrum alpinum. A leafhopper Planaphrodes bifasciata paid a passing visit during lunch (later identified, from a photograph, by Stephen Moran), a golden-ringed dragonfly Cordulegaster boltonii was hawking along the course of the burn and water crickets Velia caprai were active on the surface of a small pool.
Continuing eastwards, we crossed a long fence, and then followed the base of the limestone outcrops to the shore of Loch Urigill. An oddity noticed close to the fence was a pale-pink-flowered variety of the marsh thistle Cirsium palustre; white varieties of this thistle seem to be a feature of the area around Elphin and Knockan, but this was subtly different. The sprawling yellowish fruiting stems of broad-leaved cottongrass Eriophorum latifolium were found in several limestone flushes, as also was a solitary common frog and some late-maturing tadpoles. The spiky fruiting heads of long-stalked yellow-sedge Carex lepidocarpa were another feature of the flushes.
A further break was taken on the shore of the loch (NC232105), where we admired small purplish leaves of colt’s-foot Tussilago farfara in its natural habitat (as opposed to disturbed ground around human settlements). Autumn gentian Gentianella amarella was found in flower in short turf on the top of the low limestone cliffs and, under some shady overhangs, two of the typical ferns of the limestone, green spleenwort Asplenium viride and brittle bladder-fern Cystoperis fragilis.
We worked our way along the rocky shore, adding several new species to a list of some 120 higher plants for the one-kilometre square NC2310 compiled on the recce. They included a striking example of water avens Geum rivale with a solitary flower pointing upwards (they are usually pendant). We finally reached the large old sheiling Achaidh Glac na Feannaige (= the field of the hollow of the lazybeds) at NC234103, where we turned for home at about 1500 hrs.
A comprehensive bird list was compiled by David and Avril Haines (see below); highlights were common sandpiper and ringed plover along the shores of the loch.
Other animal life encountered included pond skaters Gerris sp., evidence of foxes and badgers, the latter especially in the shieling grasslands, a batch of moth eggs neatly spiralling around a grass stem, the large black slug Arion ater, jointed rush rosettes galled by the psyllid Livia juncorum and greenfly sheltering from predation within infolded reddish leaves of creeping bent Agrostis stolonifera.
Altogether, a most enjoyable day; threatening clouds blew away, the breeze kept both midges and clegs at bay and with our x10 hand-lenses deployed we were treated to a wide range of visual delights, both plant and animal. I would like to thank David Haines and Gwen Richards for their photographs and help in compiling this account.
Birds noted (confirmed breeding indicated with asterisk): Blackbird*, Chaffinch, Common Sandpiper, Great Black-backed Gull, Greenfinch, Grey Heron, House Sparrow*, Meadow Pipit* , Mistle Thrush*, Pied Wagtail*, Raven, Ringed Plover*, Sand Martin*, Skylark, Starling*, Stonechat*, Swallow, Wheatear*, Willow Warbler, Wren.
Ian M. Evans