Peacock Nymphalidae

Aglais io (Linnaeus, 1758)

Description: Wingspan 63-75mm. The sexes are similar, though females are larger than males. The upperside is strikingly patterned in shades of red and black. Each wing bears a large eye spot. The underside appears dark but on close inspection subtle patterning can be seen. That on the forewing is a reflection of the upperwing pattern

Similar Species: The Peacock is unmistakable as no other Irish butterfly has prominent eyespots.

Key Identification Features:

Sets:  male upperside male underside

Flight Period: Strictly univoltine. Overwintered adults emerge in March and survive to May. The new adults emerge in July and enter hibernation in September.

Status: Recorded in all parts of N. Ireland. The Peacock has been prone to large fluctuations in population and range. The largest numbers and most stable populations are in the west especially Fermanagh. Further east it may be totally absent for several years as happened in the early 1990s. Currently it appears to be expanding.

Ecology: Adults are free-ranging and can be seen in many habitats. In spring males set up territories in sunny patches on the edge of woodland. They investigate any flying object. If another male is encountered a skirmish can ensue whilst females are pursued vigorously. Once mated females lay eggs on nettle Urtica dioica, choosing large, sheltered plants. In summer the new generation adults feed on nectar sources prior to hibernating. They are attracted to a wide range of wild, garden and exotic species.

World Distribution: Central Europe and Asia Minor, across Asia to Japan.

Bradley & Fletcher number: 1597 Agassiz number: 59.026

Additional information:

UK Butterflies account


 Thompson, R. S. & Nelson, B., 2003 (Oct 2). [In] The Butterflies and Moths of Northern Ireland