A small, widespread butterfly that occasionally visits gardens. Females are similar to Brown Argus, which lack blue dusting near the body, and to female Adonis Blue, which have dark veins extending into white fringe on wing edges. The male Chalk Hill 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
- Size: Small/Medium
- Wing Span Range (male to female): 38mm
Conservation Status
- GB Red List (2022): Vulnerable
- Butterfly Conservation Priority: Medium
- European status: Not threatened
- Protected in Great Britain for sale only
Caterpillar Foodplant
The sole foodplant is Horseshoe Vetch (Hippocrepis comosa).
Lifecycle
Habitat
The foodplant and the butterfly are restricted to chalk and limestone grassland.
Distribution
- Countries: England
- Restricted to southern England, but not in the far south-west
- Abundance trend: -5% (1976-2019)
- Distribution trend: -82% (1978-2019)
Chalk Hill Blue (male/upperwing) - Iain Leach
Chalk Hill Blue (male/upperwing)
Iain Leach
Chalk Hill Blue (female/upperwing) - Tamás Nestor
Chalk Hill Blue (female/upperwing)
Tamás Nestor
Chalk Hill Blue (male/underwing) - Tamás Nestor
Chalk Hill Blue (male/underwing)
Tamás Nestor
Chalk Hill Blue (female/underwing) - Tamás Nestor
Chalk Hill Blue (female/underwing)
Tamás Nestor
Chalk Hill Blue (female/upperwing) - Tamás Nestor
Chalk Hill Blue (female/upperwing)
Tamás Nestor
Chalk Hill Blue (male/upperwing) - Trevor Wilson
Chalk Hill Blue (male/upperwing)
Trevor Wilson
Adam Gor
Chalk Hill Blue (male & female)
Adam Gor
Chalk Hill Blue (egg) - Tamás Nestor
Chalk Hill Blue (egg)
Tamás Nestor
Dean Morley
Chalk Hill Blue (young caterpillar)
Dean Morley
Chalk Hill Blue (young caterpillar) - Dean Morley
Chalk Hill Blue (young caterpillar)
Dean Morley
Peter Eeles
Chalk Hill Blue (caterpillar)
Peter Eeles
Chalk Hill Blue (pupa) - Peter Eeles
Chalk Hill Blue (pupa)
Peter Eeles