For the last four years I have been involved with an exciting project to try to create a new habitat for Grayling butterflies, Hipparchia semele.
Grayling are only known to occur in three small colonies in East Lothian. One is in a steep-sided valley, or cleugh, in the Lammermuir Hills. The other two locations are ex-industrial sites – one on a disused railway siding of an old opencast coal mine called Blindwells, the other a re-landscaped tip from an old coal mine called Meadowmill.
The colony at Blindwells was discovered in 2009 and it is suspected that Graylings could have been there for a few years before that. In 2011 they were found on the old coal tip at Meadowmill, which is just across the road. This colony is now the larger of the two and I think the maximum count of Grayling seen there was 80.
There have long been plans to build a new town at Blindwells, but there seemed to be so many issues surrounding this that we doubted it would ever happen. However, in 2017 we were alarmed to see fencing going up around the site and bulldozers moving in.
So, very quickly, a plan was hatched. The idea really came from a countryside volunteer who persuaded the East Lothian Countryside Rangers that we should try to translocate the Blindwells Grayling colony to somewhere safe.
East Lothian Council own another ex-industrial site, Levenhall, which is being restored for recreation and wildlife. The Countryside Ranger who works there identified a perfect south-facing slope. I just happened to be in the office one day and overheard the Parks Manager complaining that he was going to have to pay to dispose of a few hundred tonnes of crushed concrete from a depot that had been demolished. This, we thought, would make the perfect material to create a new Grayling colony.
In 2018 we attended the AGM of the East of Scotland branch of Butterfly Conservation, where they said that there was funding available for projects. Perfect, we secured funding to scrape the top soil from a site about 50 metres long by 30 metres. On one side we spread the crushed concrete in three long piles to replicate the railway sidings and on the other side of the site we asked the contractor to leave random piles of crushed concrete. Hopefully this would provide a variety of different slopes and orientations.
With the help of more volunteers, including the Junior Rangers, we removed rubbish (it is amazing how much wire and plastic there was amongst the concrete). The area was then seeded with Red Fescue and Sheep’s Fescue (the foodplant of the Grayling caterpillars) and dry meadow mix wild flower seeds were scattered along the lower slope. Between the two areas was a grassy strip, which has also had wild flower seeds, including Yellow Rattle sown.
The next problem was how to get the butterflies there. We devised several plans. Initially we searched for caterpillars at Blindwells. We were told they were easy to find at night using a torch, as they climb up grass stems to feed. Five of us crawling in the grass one night for two hours unearthed one caterpillar in May 2018.
So, we then decided to try to locate eggs in August. The sidings at Blindwells were now protected by Heras fencing, but we needed permission and full protective clothing to get in and this had to be arranged a few weeks in advance. By the time we managed to get in we discovered the site covered in dust with a diesel generator running next to it. Sadly, we found no eggs.
So in July 2019 we decided to look for eggs at Meadowmill. They were reasonably easy to find and we collected 36 eggs and we took them to Levenhall, where they were put on the now well-established Fescues.
In the summer of 2020 we regularly monitored our new site in the hope of seeing adult Grayling flying, but sadly none were seen. So, in July the Countryside Ranger caught 12 adult Graylings at Meadowmill and translocated them to Levenhall. They were put in a cage overnight, which was removed early the next morning. Five of them were still there at lunchtime, so we hoped they may have laid some eggs.
Unfortunately, we didn’t manage to record any adult Grayling there again in the summer of 2021. So, it looks as though that attempt may also have failed.
Creating a new site for Grayling butterflies has never been done before, so we made it up as we went along. We had a lot of good fortune and it has been really exciting to be involved in such a project.
We are now wondering if there is some crucial element missing from our new site. We have a south-facing slope with Fescues growing on it, but what else could it need. Two of the existing colonies are associated with coal, but the other colony is in a natural valley. Do they need a particular chemical make up in the soil, is there some sort of symbiotic relationship with ants, possibly it is something even more subtle such as bacteria, or a fungus that is required. Maybe things will change over time.
We will certainly keep monitoring the site and consider how we can persuade Graylings to move in. Last year 17 species of butterflies were recorded at the new site, so it is clearly attractive to butterflies.
