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Butterfly Conservation- Glasgow & South West Scotland Branch

Peacock (Inachis io)


The Peacock is one of Britainís most easily recognised butterflies. Its crimson and black wings (wingspan 63-75 mm) have large colourful eye spots on the upper surface in the corner of both front and hindwings. The dark brown underwings are beautifully camouflaged to enable the adults to remain undetected while they overwinter in crevices in tree bark or in dead leaves (or in your tool shed!). The eye spots of the peacock may act as a deterrent to predators that might be surprised by the sudden appearance of large eyes looking at them, and also function to misdirect any determined attack away from the body of the insect. .

Credit: Jim Black
Credit: Scott Shanks
Credit: Jim Black

Life Cycle

The adults emerge from hibernation during warm days in spring. In south west Scotland the adults tend to be seen in numbers from mid-March onwards. Males feed during the morning on willow blossom and other spring nectar sources before setting up territories which they defend from intruding males and search for females. A single brood is produced each year. Females search for large patches of common nettles (Urtica diocia) in full sun, where they lay large clusters of green spherical eggs on the undersides of the nettle leaves. The caterpillars are black with white speckles and long black spines. They initially stay together, feeding within a silken tent for protection. Before pupation larger larvae disperse to feed separately. The green-brown pupa is formed hidden in dense vegetation. The new generation of adults emerge in August and set about feeding at rich nectar sources to build the fat reserves they require to see them through winter. The adults also seek out potential hibernation sites such as crevices in trees or walls or unheated buildings. Once they find somewhere suitable they will remain in the area, feeding during the day and roosting at the site at night until it enters hibernation from late September onwards.

Flight Times

In South West Scotland adults can be found on the wing from February right through to December, with numbers of the overwintering adults peaking in April/May and the summer brood of adults emerging from mid-August and remainig active through September when they are commonly seen feeding on Buddleia. Local populations are augmented by migrants from the continent in late summer.

Habitat & Distribution in SW Scotland

Distribution map 2010

The Peacock is a highly mobile species and can be found almost anywhere in South West Scotland where nectaring sources can be found, but is most common in parks and gardens of urban areas or along the coast. It can frequently be found feeding in gardens or woodland glades or flower-rich meadows where the flowers of knapweed and thistles are particularly favoured.

The Peacock has made a dramatic northwards expansion of its range since the turn of the Millennium. It seems always to have been more common in western and southern Scotland as far north as northern Argyll and is seen in some years on some of the western isles including Islay, Colonsay, Rhum & Mull.  Further north and east, the Peacock has occurred sporadically with higher numbers being found after large migrations from the continent but little overwintering of adults was observed. Therefore numbers have varied a lot from year to year. However, the situation changed dramatically in 2002, and literally overnight when a large migration into Scotland on 11 September 2002 led to a significant increase in the range in northern Scotland. This range expansion extended further north during 2006.

This dramatic range expansion is detailed in the Atlas of Butterflies in Highland & Moray which shows that the Peacock is now well established north of the Caledonian Canal with many observations of successful overwintering of adults in woodstacks, sheds and occasionally houses. In 2008 Butterfly Conservation Scotland held a nationwide postcard survey of the distribution of the Peacock to document this recent significant range expansion and it has demonstrated this big change in north west of Scotland in particular. While climate warming has almost certainly played a role, the Peacock has been known to be widespread and abundant in Scotland in earlier years such as 1955, 1975 & 1976 but scarce in others. Clearly numbers fluctuate in response to sporadic immigrations from the continent with the 11 September 2002 being a particularly dramatic and successful example.


  • Barbour, D., Moran, S, Mainwood, T & Slater, B 2008. Atlas ofr Butterflies in Highland & Moray. Big Sky.
  • Futter, K., Sutcliffe, R., Welham, D., Welham, A., Rostron, A., MacKay, J., Gregory, N., McCleary, J., Tait, T., Black, J. & Kirkland, P. 2006. Butterflies of South West Scotland. Argyll Publishing. (see Atlas page)
  • Asher, J., Warren, M, Fox, R., Harding, P., Jeffcoate, G., Jeffcoate, S. 2001. The Millennium Atlas of Butterflies in Britain & Ireland. Oxford University Press.
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  • Fox, R., Asher, J., Brereton, T., Roy, D., Warren, M. 2006. The State of Butterflies in Britain and Ireland. Pisces Publications.
  • Thomson, G. 1982. The Butterflies of Scotland. Croom Helm London.
  • Tomlinson, D. & Still, R. 2002. Britainís Butterflies. WILDGuides.

Written by Scott Shanks & Andrew Masterman

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