Large Blue

Maculinea arion


Despite its name, the Large Blue is actually a fairly small butterfly but the largest of our blues. Adults fly for a very short period from the end of June to the beginning of July. Always rare in the UK, it declined dramatically during the 20th century and became extinct in 1979. Reintroduced in the early 1980s, small populations are now surviving in the south of England. It breeds in warm, dry unimproved grasslands such as coastal or limestone grasslands.

How to identify

The Large Blue is a fairly dark blue butterfly with thick, dark grey wing borders and large dark spots on the forewings. It is larger than the other blue species, and only found on a handful of sites.

Where to find it

A very rare butterfly, only found at a handful of sites in the south of England where it has been reintroduced.


When to find it

  • June
  • July

How can people help

The Large Blue butterfly became extinct in the UK in the 1970s due to habitat loss, but has since been successfully reintroduced. The Large Blue Recovery Programme now runs in the south of England to help to protect this species, and The Wildlife Trusts are one of a number of partners involved ensuring proper management of grassland sites and monitoring of populations. You can help this enigmatic insect by supporting The Wildlife Trusts and becoming a member.

Species information

Common name
Large Blue
Latin name
Maculinea arion
Butterflies and moths
Wingspan: 3.8-5.2cm
Conservation status
Classified as Near Threatened on the IUCN Red List. Classified as a Priority Species in the UK Biodiversity Action Plan.