The Common Blue is the most widespread blue butterfly in Britain and Ireland and is found in a variety of grassy habitats.

The brightly coloured males are conspicuous but females are more secretive. The colour of the upperwings of females varies from almost completely brown in southern England to predominantly blue in western Ireland and Scotland, but the colour is variable within local populations with some striking examples. Unlike Adonis and Chalkhill Blues, the dark veins do not extend into white fringes of wing margins.

It remains widespread but there have been local declines within its range. 

Size and Family

  • Family: Blues
  • Size: Small
  • Wing Span Range (male to female): 35mm

Conservation Status

  • Butterfly Conservation priority: Low                         
  • European status: Not threatened

Caterpillar Foodplants

Common Bird's-foot-trefoil (Lotus corniculatus) is the main foodplant. Other plants used include: Greater Bird's-foot-trefoil (L. pedunculatus), Black Medick (Medicago lupulina), Common Restharrow (Ononis repens), White Clover (Trifolium repens), Lesser Trefoil (T. dubium).



Very common and found in a variety of habitats especially sunny sheltered spots. Examples of habitats include; downland, coastal dunes, undercliffs, road verges, acid grass and woodland clearings

It is also found on waste ground, disused pits and quarries, golf courses, and urban habitats such as cemeteries.


  • Countries: England, Ireland, Scotland and Wales
  • Found throughout Britain and Ireland
  • Distribution Trend Since 1970’s = -15%

Common Blue (male/upperwing) - Peter Withers

Common Blue (male/upperwing)

Common Blue (female/upperwing) - Iain Leach

Common Blue (female/upperwing)

Common Blue (male/underwing) - Andrew Cooper

Common Blue (male/underwing)

Common Blue (female/underwing) - Dean Morley

Common Blue (female/underwing)

Common Blue (male & female) - Ivan Lynas

Common Blue (male & female)

Common Blue (egg) - Gilles San Martin

Common Blue (egg)

Common Blue (caterpillar) by Peter Eeles

Common Blue (caterpillar)

Common Blue (pupa) by Peter Eeles

Common Blue (pupa)