Which butterfly is called the European peacock?

The European peacock butterfly is Aglais io.

Aglais io is a widespread Eurasian butterfly named for the large eyespots on its wings. Each forewing carries a prominent eyespot with blue, yellow, and black details. When the butterfly suddenly opens its wings, the spots can startle predators; when it closes them, the dark underside helps it resemble a dead leaf.

The species is common in gardens, woodland edges, parks, and other habitats where its caterpillar food plant, stinging nettle, grows. Adults may hibernate through winter in sheltered places such as sheds, tree cavities, and buildings. They can emerge on warm days before many other butterflies.

The European peacock is sometimes confused with the North American mourning cloak, Nymphalis antiopa, because both have dark wings and conspicuous markings. They are separate species in different genera. The historical scientific name Inachis io is a former combination still encountered in older references.