The small blue butterfly (Cupido minimus) is the UK’s smallest butterfly, with a wingspan of only 16-27mm. It’s a beautiful little butterfly, recognised by the dark blue on the upper surface of its wings and dark spots on the silver-blue underwing. It flies from mid-May to August and lays its eggs on the caterpillar food plant, kidney vetch. As is the story with much of our UK wildlife, unfortunately the small blue has experienced a decline in both population and distribution over the whole of the UK.
This decline has been noticed locally, with the number of adults seen at Parc Slip Nature Reserve outside Bridgend in South Wales slowly reducing over the years. In 2012, the Wildlife Trust of South and West Wales enlisted the help of local Bridgend school children to improve the habitat for small blue on Parc Slip to see if we could boost populations on the reserve again.
Kidney vetch seeds and planting kits were sent out to two local primary schools, Oldcastle and St Roberts, where the children planted the seeds and grew them in their classrooms. Once the seedlings began to emerge, the plants were brought to Parc Slip and planted out on the reserve.
Now we have some very good news to report! The kidney vetch has been growing steadily over the last two years and this year has produced a wonderful display of flowers. On Friday 20th June, staff from the Wildlife Trust were thrilled to find a female butterfly near the kidney vetch. Since then, numerous larvae have been found feeding on the kidney vetch and there have been a number of reports of small blue on the nature reserve by visitors.
Thank you very much to the local school children for planting and growing the seeds in their classroom, and to Biffa Award for funding the project.