Monday, 28 May 2018

Visit to Fleam Dyke. 20th May 2018.

Five members turned up for this, our second visit to this area of Cambridgeshire in two years. Jim Fish was our leader on this occasion. The weather was warm and sunny, with a light SE breeze; perfect for this kind of walking.

Beginning at the entrance to Fulbourne Nature reserve, we took to the trail through a small woodland, leading out onto open meadows, full of Red Clover and Buttercups, as well as a sprinkling of other chalkland flowers and plants.  The flowery meadows soon gave way a somewhat wetter meadow, where sporadic orchids could be seen – eventually being identified as Southern Marsh Orchid, before leading to a wetter, slightly harsher environment, where we had to look more closely for orchids amongst the varied plant life; though once again mainly comprising Southern Marsh Orchid and one or two spikes of Spotted Orchid. It was felt by everyone that generally, orchids were flowering later than last year probably due to the long, harsh winter; even so we were here a week earlier than last year, so that could also be a contributary factor. But the general lack of butterflies such a Common Blue, was also an indication of last year’s cold spring, as was the birdlife, which was much less in evidence than previously, with no Cuckoo; no Swifts and no Swallows (although the latter two species did make a brief showing later in the day). Before we reached the dyke proper, Tim found two Common Buzzards soaring over fields on thermals high into a pristine blue sky.

And then on to Fleam Dyke, with just a lone Azure Damselfly and a singleton Cockchafer Beetle (only the second I’d ever seen) which posed nicely on Aspen for a second or two before falling to the ground where it was lost to view. Most of the group missed this.
Once on the dyke, it was quite apparent that there had been substantial clearance of undergrowth over the winter months, and really it had needed it badly, to promote the growth of more wild flowers and thereby foodplants for Green Hairstreak Butterfly in particular, and our target species for the day. 
Already Brimstone Butterflies were well in evidence, and through the rest of the morning into the afternoon several species were observed, though none in profusion, and these were: - Holly Blue Butterfly (2); Common Blue Butterfly (2); Brimstone (over 40 individuals); Large White; Small White; Green-veined White (1); Green Hairstreak (probably at least 10 individuals allowing for possible duplication); Small Heath (2) and Orange Tip.  A Burnet Companion Moth, and a Green Carpet Moth (for me arguably even more attractive than the stunning Green Hairstreaks) were the only moth species identified.
Bird species were not very well represented, which was quite surprising, but could be said to reflect the lack of spring migrants generally thus far; but nevertheless, included several Common Whitethroats; a Willow Warbler; Chiffchaff; Great Spotted Woodpecker; Goldfinches; Linnet; Blackbird; Bullfinch and Yellowhammer (heard only); Jackdaw; Carrion Crow; Rook; 2 Swallows and 2 Swift. But no Corn Bunting this year.
Flower species included Twayblade; Southern Marsh Orchid; Spotted Orchid; Musk (or Nodding) Thistle; Chalk Milwort; Salad Burnet; Common Rock Rose; Cowslip; as Ox Eye Daisy and a few isolated stands of attractive Columbine.

After a welcome lunch stop at the ancient Mutlow Hill site - a Bronze-Age round barrow - we observed more Green Hairstreaks on the way back - some literally flying round our feet - but being almost constantly on the wing, were extremely difficult to photograph well. I was the only one to get a fleeting glimpse of what was likely to have been a female Black-tailed Skimmer following us along the trail, but it soon disappeared so I couldn’t be certain I’d identified it correctly.
It was an interesting day out, the highlight arguably being the unexpectedly good numbers of Green Hairstreaks, some seen reasonably well; and with excellent weather with no rainfall or strong winds, we were all glad we came.
David Sampson