The Peacock is widespread, common in all but the north of England and Scotland, where it only reaches the southern parts. It's found mainly in gardens, although you can also see it in open fields, downland and woodland.
The Peacock's caterpillars eat only stinging nettles.
This is a single-brooded butterfly but, in captivity, it can be persuaded to breed again in July. There have been some reports of late larvae in the wild, turning into adults before hibernation. Hibernation begins at any time from August to early October and some can be found flying even later. The Peacock makes a strange rustling sound, like a hiss, when it opens and closes its wings. If a hibernating group are disturbed you can hear the noise. Early adults are on the wing from March onwards although, in fine weather, they may make short flights much earlier.
The female lays a large batch of eggs on the undersurface of a nettle leaf near the growing shoot. They are pyramidally stacked several deep. The larvae spin a web of silk and feed within on the leaves, moving to a new site with a new shelter constructed as food supplies require. Though blacker than the larvae of the Small Tortoiseshell they can be confused, partly because the Small Tortoiseshell larvae vary in colour and can be quite dark. When larger the Peacock larvae are jet black, spinier and peppered with clear, round white flecks. This species is much less frequently seen in the larval stage than the Small Tortoiseshell. Peacock larvae remain gregarious until shortly before pupation, but in the last instar they spread out considerably. The caterpillars of the same brood apparently mature almost simultaneously and there are reports of them all marching off as one to pupate. Certainly they choose the same day to disperse to pupate, and next day only a few stragglers remain. The caterpillar, in common with other closely allied species, hangs up to pupate, suspended by the tail alone. The pupa has two colour forms, with degrees between the two, from a rather grained khaki colour tinged with brown to a pale lime green, flecked with maroon and with traces of spangles in silver and gold. This compares with the gold form of the Small Tortoiseshell pupae, occur ring in those which have formed on the foodplant in captivity.
The butterflies are usually numerous, particularly in gardens, from the end of July until September, with some late into the autumn. They particularly favour the flowers of buddleia, also lucerne, thistle, knapweed, marjoram and clover.