Chalk Hill Blue - Polyommatus coridon

The sexes are strongly dimorphic; the males being a pale sky blue, and the females being a chocolate brown.

Chalk and limestone grassland. This species lives in discrete colonies where its foodplant, Horseshoe Vetch, is found in abundance. It is also a warmth-loving butterfly, and is typically found on sheltered, south-facing hillsides.

Mainly from July to September.

The primary larval foodplant is Horseshoe Vetch.

The distribution of this species follows the distribution of Horseshoe Vetch which, in turn, follows the distribution of chalk and limestone grassland. This species is therefore restricted to England, south east of a line running from West Gloucestershire in the west and Cambridgeshire in the east. This species is absent from most of central England, northern England, Scotland, Wales, Ireland, the Isle of Man and the Channel Islands.

Very local and uncommon in Leicestershire and Rutland.