Small Blue

• Latin name: Cupido minimus
• Family group: Blues
• Countries: England, Scotland, Wales, Ireland
• Size: Small

Resident

Range declining.

Our smallest resident butterfly is easily overlooked, partly because of its size and dusky colouring, but partly because it is often confined to small patches of sheltered grassland where its sole foodplant, Kidney Vetch, is found.

Males set up territories in sheltered positions, perching on tall grass or scrub. Once mated, the females disperse to lay eggs but both sexes may be found from late afternoon onwards in communal roosts, facing head down in long grass. The butterfly tends to live in small colonies and is declining in most areas.

Conservation status

• UK BAP status: Proposed Priority Species
• Butterfly Conservation priority: high
• European threat status: not threatened
• Fully protected in Northern Ireland, protected in Great Britain for sale only

European/world range

Throughout Europe from north Spain to Scandinavia, and across Asia and Mongolia. Declining in some countries of north-west Europe, but stable elsewhere.

Foodplants

The sole foodplant is Kidney Vetch (Anthyllis vulneraria). The larvae live only in the flower heads where they feed on developing anthers and seed.

Habitat

The butterfly breeds in a range of dry sheltered grasslands where Kidney Vetch grows, including: chalk and limestone grassland, coastal grassland and dunes, and man-made habitats such as quarries, gravel pits on eskers, road embankments, and disused railways.

Sites are usually sheltered and contain sparse or eroding vegetation where Kidney Vetch seedlings can become established and where flowering plants are abundant. The best habitats typically contain a mosaic of short and tall vegetation and patches of light scrub.