An insight into a day's square-bashing

For those who are unfamiliar with the concept of square-bashing, I thought it might be instructive to show how I approach the subject. The map below depicts the route I took on 9 June between Mallaig and Fort William. It involved a total of ten stops, mainly on roadside verges as real 'sites' are often hard to come by. Where I can, I try to stop by a stream or woodland so that there is potential to collect Nematocera for the Cranefly and Fungus Gnat schemes. In other places I stop for a matter of minutes when I spot somewhere that might yield a few hovers: after all, every record counts!

Map 1. Locations of sampling points when square-bashing on 9 June 2017. The first five sites took approximately 3 hours and the remaining sites were visited quickly on the return trip. I arrived at site 1 at around 10.15 and headed for home from site 10 around 3.45, reaching Kingussie at 5.45. The total round trip was about 180 miles. In the process, 6 ten kilometer squares were visited and a small number of hoverfly records was generated.

On this day, my aim was to cover part of the west coast that is very poorly recorded. The day was not ideal – a mixture of sunshine and showers – and there were very few nectar sources. So, apart from checking out the occasional roadside Rowan, it was a matter of sweeping to generate the majority of records.

Even so, I did find two very nice localities. The first was a lovely iris flush running to the shoreline, which is very characteristic of the west coast of Scotland Location 6 (photo 1); the second (Location 9, photo 2) was a delightful section of stream with adjacent meadows covered in pignut and with localised patches of brambles and dog rose. Both were pleasant and the second site yielded a reasonable list of hoverflies. Nevertheless, hoverflies were thin on the ground and I did far better for Nematocera.

Photograph 1. Flushed shoreline with iris beds abutting saltmarsh in a continuous transition.

Photo 2. Damp meadow with bramble and dog rose.

When recording Nematocera I simply hoover up everything that flies like a cranefly or gnat and then sort them when I get home. I often end up with a pooter full of small flies and refer to it as 'black grot' – which is frowned upon by Peter Chandler as he loves fungus gnats. Photographs 3 and 4 show the results – the pile of specimens for sorting, and the subsequent piles of gnats and craneflies. I'm afraid neither shot is terribly good as it was taken in the rather restricted light of my hotel room and there was probably an element of camera shake given long exposure time (I'm no photographer!). Out of this morass I also identify what I can from other families, and pin a small amount of specimens for identification in the winter (or a winter!). The end result often yields records of Lauxaniidae, Empididae, Dolichiopodidae, Tephritidae and Larger Brachycera, so lots of schemes benefit in the long-run.

Photo 3. Sample of flies collected before sorting. Whilst predominantly Nematocera (standard bird-food) there are also a range of other families and Orders, with a large green sawfly prominent on the right hand side, and several yellow Lauxaniids in the pile.

Photo 4. sample of Nematocera separated into craneflies and fungus gnats.

This is the sort of recording that others might wish to try. It is arguably the most effective way of making sure that one uses one's time efficiently and makes sure that as many schemes as possible benefit from what is a very expensive trip. I will post more on the results when I get data back from Alan and Peter.