Peacock butterflies (Aglais io) are now coming out of hibernation and appearing in our gardens. They will have spent the winter in sheltered refuges such as hollows in trees or garden sheds.
The Peacock is unmistakable, with spectacular eyes on the upperside of the hindwings resembling those on a Peacock’s feather and will appear very threatening to predators. The underside is quite different, being almost black, providing perfect camouflage when the butterfly is at rest on a tree trunk, or when hibernating. In addition to camouflage and large eyes, the butterfly is able to make a hissing sound by rubbing its wings together that is audible to human ears. The sexes are similar in appearance, but females are slightly larger.
In early Spring the newly awaken butterflies will now mate and the female will lay its eggs in large batches. The eggs will be placed on the leaves of Stinging Nettle (Urtica dioica) and Hop (Humulus lupulus), so it useful to have some of these larval food plants in your garden. See our blog on Food for Caterpillars with a downloadable plant list (https://pollinatorproject.gg/2018/04/03/food-for-caterpillars/). The caterpillars live in groups, protected by a web of silk, before dispersing to pupate and emerge as the next generation of adult at the end of July. Peacocks are generally single-brooded, however, in good years, a small second brood may appear.
Adult butterflies drink nectar from a wide variety of flowering plants, including Buddleia, Dandelions, Oregano, Verbena, Hemp Agrimony, and Wallflowers; they also like tree sap and rotten fruit.