Males have milky blue wings with thin black-brown border and thin white fringe. Females brown with orange spots and blue dusting near body.
A small, widespread butterfly that occasionally visits gardens. Females similar to Brown Argus, which lack blue dusting near body, and to female Adonis Blue, which have dark veins extending into white fringe on wing edges. The male Chalkhill Blue is paler and, apart from the Large Blue, larger than other blue butterflies seen in Britain and Ireland.
At some sites many hundreds may be seen in August, flying just above the vegetation, searching for females. Large numbers of males may also congregate on animal dung and other sources of moisture and minerals. Females are much less conspicuous, being duller in colour, more secretive in their habits, and spending less time than the males in flight.
The butterfly is confined to calcareous grassland in southern England and has declined in some areas during recent decades.
Size and Family
Family – Blues
Small/Medium Sized
Wing Span Range (male to female) - 38mm
Conservation status
UK BAP statusNot listed
Butterfly Conservation priorityMedium
European statusNot threatened
Protected in Great Britain for sale only
Caterpillar Foodplant
The sole foodplant is Horseshoe Vetch (Hippocrepis comosa).
Distribution
Countries – England
Restricted to southern England, but not in far south-west
Distribution Trend Since 1970’s = -36%.
Habitat
The foodplant and the butterfly are restricted to chalk and limestone grassland.
