Chalk Hill Blue

Posted by

Chalk Hill Blue butterfly

The chalkhill blue is a butterfly in the family Lycaenidae.
Scientific name: Polyommatus coridon
Higher classification: Polyommatus
Rank: Species
Order: Butterflies and moths
Family: Lycaenidae
Kingdom: Animalia

Scientific classification

  • Kingdom: Animalia
  • Clade: Euarthropoda
  • Class: Insecta
  • Order: Lepidoptera
  • Family: Lycaenidae
  • Genus: Polyommatus
  • Species: P. coridon
  • Binomial name: Polyommatus coridon

Chalk Hill Blue Description

Polyommatus coridon has a wingspan of 30–36 millimetres. These small butterflies present a sexual dimorphism. This species’ physical appearance can be described as males having pale silvery-blue upperside of the wings with a submarginal line of gray spots on the hindwings and a thin brown and white chequered fringe. Females have dark brown upperside of wings, with marginal orange spots and also with chequered fringes.

About Chalk Hill Blue

The Chalk Hill Blue is found on chalk downland, although limestone downland is also used. The adult butterfly is most-often seen in bright sunshine, where the ground may appear to shimmer with the activity of hundreds, if not thousands, of males searching for a mate just a few inches above the ground.

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.


This species is single brooded, with a protracted emergence beginning in early July and continuing into late August, with the last individuals often seen well into September.

The reticulated, dome-shaped whitish eggs are laid singly on stems of horseshoe vetch Hippocrepis comosa or on nearby grass stems in August. During the winter they are washed off by the rains and lie on the surface until the spring. The larvae are fully formed within the eggs in the autumn, but do not hatch until the following March or April.

Chalk Hill Blue Habitat

This particular species of butterfly has a preference for dry calcareous grasslands, at an elevation of 100–2,000 metres above sea level. This species also has a preference towards grasslands that have short grass with many flowering plant. P. coridon is a sedentary organism which means that they do not travel very far within their habitat range. These individuals have the tendency to stay within their habitat patch rather than do long migrations to find new habitats.


The butterfly, when it emerges in July, has to break through the soil and find it’s way to a stem from which it can hang to dry it’s wings. The adults often emerge en masse, and can sometimes be found basking in hundreds on low herbage early in the mornings.

Favourite nectar sources include marjoram, stemless thistle, carline thistle, knapweeds, wild basil, self heal and thyme, although they will also visit bramble, ragwort, yarrow and hemp agrimony. They also occasionally gather in small groups on mammal dung.

Also more: Brown Hairstreak butterfly

Chalk Hill Blue images

Reference site:

Related Posts

Leave a Reply

Your email address will not be published.