By Sarah Bird, Species on the Edge Senior Project Officer for the North Coast, Plantlife
Back in January of this year, we published a blog post on an exciting upcoming project on the North Coast: a Butterfly Bank! We are now delighted to bring you an update. Here’s how things went 👇
Butterfly bank construction began in spring of 2024. With the Small Blue butterfly being the target beneficiary species of the bank, we prepared the bank to benefit the sole foodplant of Small Blue caterpillars – Kidney Vetch. Kidney Vetch grows best in poor, stony ground which is why we created the bank out of quarry waste (donated by Barrock Quarry – thank you!) and sand. We planted Kidney Vetch seedlings that had been grown by volunteers; the Kidney Vetch should do well in these conditions without competitors who aren’t as keen on the stony, sandy ground. We also planted Bird’s-foot-trefoil, Thrift and Wild Thyme which are also popular flowers with caterpillars and butterflies.
An anxious wait followed the construction and planting of the first Butterfly Bank at Dunnet Community Forest in spring 2024. The ‘Butterfly Bank Crew’ (BB Crew) were waiting for the Small Blue butterflies, which usually emerge in late May in Caithness. Excitement and anticipation filled our heads. But, had we got it right? Would the Small Blues visit the butterfly bank? Had our efforts been worthwhile?
Expectations built further at our Small Blue Day on 12th May, when we really started to get motivated and ready for the emergence of these amazing little butterflies, reminding local volunteers and visitors what they look like and where to go to see them. It was a beautiful sunny day, and a few kidney vetch flowers were just starting to open, which seemed a good omen…
Just a day after Small Blue Day we had the first 2024 Caithness Small Blue sighting at Castlehill; warm weather seemed to have bought the butterflies out early. The nice sunny weather continued for much of May in Caithness, and the butterflies were seen quite frequently at the known sites. On the 19th May our most enthusiastic Scottish Countryside Junior Ranger, Daniel Parlour, spotted a Small Blue on a broom bush near the butterfly bank, and on the 27th May I had a thrilling email from a lady who was on holiday in Caithness and visiting Dunnet Forest. It said:
“At least 8 Small Blue butterflies at Dunnet butterfly bank today. Margaret”
Wow, thank you Margaret! That was probably my best email of 2024!
Not only had the butterflies found the butterfly bank, but our route markers worked too. Margaret had followed the colourful signs made by the UHI Supported Learning Group from the carpark to the bank. Then she had recognised a Small Blue butterfly, and used my email from the sign there to let me know. I passed the message around the team and we all heaved a sigh of relief. I visited the following day and saw around 17 Small Blues in the meadow around the bank, and a couple of butterflies on the Kidney Vetch plants we had carefully planted there. By the end of May all the BB Crew had seen Small Blues on or near the Butterfly bank.
June was cold in Caithness and Small Blue numbers dropped, never again reaching the peaks we saw in late May. Our great team of 10 volunteers completed Timed Count surveys at six different sites in the Thurso/Castletown area and got a couple of new Small Blue sightings on the coast at Murkle as well. The last record I know of at the butterfly bank was a single Small Blue on the 7th July.
I received another few email records as a result of the signs. One message on the 2nd August contained a video of a possible Small Blue butterfly, which was very late, and would have been from a second brood if confirmed. I sent the video around the BB Crew and experts and we concluded that it was a Common Blue. However, this did prompt the survey volunteers to go out in early August to check for second brood Small Blues – none were seen, but it was exciting to look.
Daniel took on management and monitoring of other wildlife at the BB over the summer, carefully removing unwanted plants and keeping track of how the Kidney Vetch was doing. All his detailed observations will help with the plans for Butterfly Bank #2 in 2025. He also showed the butterfly bank to a group of volunteers who visited in August to help with habitat management at Dunnet Community Forest.
In all, I think we can call Butterfly Bank #1 a big success, and we hope to build on that success with the next phase. Butterfly Bank #2 will be bigger and better: we want it to provide more shelter from the wind; we want to keep more stone exposed for basking butterflies; and we will try to remove more of the weeds from the sand. A big thank you to everyone made the butterfly bank possible – the Species on the Edge North Coast team, Caithness Environment Volunteers, Dunnet Community Forest volunteers, our Small Blue Ambassadors from UHI NWH Thurso and those who grew the Kidney Vetch seedlings from seeds. And thank you to all those who have sent in records, made signs, done timed counts, helped with habitat management and supported in other ways; we couldn’t have done it without ALL of you. This species on the edge is getting a real boost in Caithness.
