Small Blue Butterflies

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. Due to this decline, the butterfly is a Priority Species on the UK Biodiversity Action Plan.

Small blue butterflies by MJ Clark

Small blue butterflies by MJ Clark

Past surveys by local volunteer Mike Clark have showed that the butterfly has been present in previous years at Parc Slip, with adults, larvae and eggs found in a number of locations on the reserve. This year, the Wildlife Trust of South and West Wales enlisted the help of local school children to improve the habitat for small blue on Parc Slip and see if we can 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. The mounds of earth around a newly dug pond near the Northern Wetlands were the perfect place to plant the seedlings as kidney vetch flourishes best on disturbed soil. St Roberts Primary School visited the reserve themselves to plant their seedlings and combined it with some pond dipping, bug hunting and reptile rambling! Oldcastle were unable to visit but kindly allowed our Wildlife Watch group to plant the kidney vetch for them on one of their Saturday meetings.

The seedlings have grown well over the summer so hopefully we will have a wonderful flowering new patch next year to be colonised by small blue. Thank you very much to our local schools for taking part in this small blue conservation project, we hope to see you back looking for the butterflies next year!