Myself and Roger Morris travelled to Kirkwall to deliver a training course: Introduction to Hoverfly Identification for the Orkney Record Centre on the weekend of the 6-7th June. To make the trip more worthwhile, we spent nearly a week getting to Orkney and a further week getting back, via the north and west coast of Scotland to undertake some recording in these remote and poorly recorded areas.
Spring in Scotland seems to have been very cool and wet this year and the season is a very late one. For example, we visited Kingussie in the first week of June 2014, and we would estimate that, by comparison, the 2015 season was 3-4 weeks behind in terms of what was flowering. In 2015 early spring plants such as Celandine, Bluebell, Wood Anemone, etc. were still in full flower and Rowan was not yet in blossom (and in many cases, flower buds were not even yet evident on the Rowan). In contrats, lants such as Chickweed Wintergreen and Heath Spotted Orchid, which were much in evedence in 2014, were not detectable at all. We were also experienced a good deal of cool, windy and wet weather with tempertaure on many days not exceeding 10°C.
We went via the Scottish borders with the intention of visiting the Whitlaw Mosses NNR to look for Cordilura ustulata. This fly was discovered on Murder Mooss in May 1991 by J.M.Nelson ([1]) when he found seven specimens between 7 and 22 May. As far as I know, the species has not been found again in Britain. Unfortunatly, Nelson does not describe either the localion or the habitat where he found C. ustulata in any detail - his only comment is "swept from Carex" - and that would describe most of the site!
We visited Murder Moss and Nether Whitlaw Moss on 1st June. The weather was dry and sunny, but extremely windy and rain arrived in the early afternoon (at which time we left!). Despite prolonged and assiduous sweeping, we did not find C. ustulata although other species such as C. pubera were quite abundant - especially on Nether Whitlaw moss. These are impressive sites and there seems every reason to expect that C. ustulata is likely to still be present.
One of the aims of travelling around the north and wests coasts of Scotland was to look for coastal Scathophagids - especially to see how widespread Scathophaga callida might be. In this we failed almost completey! A combination of bad weather (low temperature and too windy to sweep) but also because we found that, whilst there is no lack of coast, we could find very few localities suitable for coastal Scathophagids. Our experience in other parts of Britain, and with S. callida in the Hebrides, is that longer vegetation high up on the shore, especially where freshwater trickles and seepages come down to the shore, are the best places to find S. litorea, S.callida and Ceratinostoma ostiorum. Generally, we found that coastal areas in north and west Scotland were so over-grazed that there was no longer vegetation. Anyway, we found no S. callida at all and S. litorea on only one site in Orkney and two on Skye.
We did find Gimnomera tarsea at many locations where we swept. At most of these, there was no obvious sign of Marsh Lousewort (although, given the season, we were probably too early for the plant to be very obvious). However, Common Lousewort was much in evidence whenever we found the fly.