The hibernators
Some of the most recognisable of our British butterflies survive as adults all through the winter, hibernating in sheds or tucked away in foliage and even log piles and rabbit holes. Comma, red admiral, peacocks and brimstone are just some of the butterflies that sleep through winter in their most familiar life stage. They are woken when temperatures rise so are sometimes seen on warmer days in the depths of December and January. As flowers are lacking, they may find rotting fruit to feed on to top up their fat supplies. Many of these species have dark mottled underwings, excellent camouflage as they sleep with their wings closed, resembling bark or a dead leaf. If your garden contains winter-flowering plants, they could be a life saver for butterflies woken by warmer winter temperatures, providing them with food and energy to last until spring.
Larvae in the ground
By far the most common way for butterflies in Britain is to overwinter either as a caterpillar in their larval stage, or as a chrysalis. To protect their soft and vulnerable bodies, caterpillars head to the bottom of plants and tuck away there or just under the earth or leaf litter where they wait, hopefully undisturbed, until spring. This tactic is used by 42 of our species, including orange-tips and common blue.
Safe and sound
One of the safest ways of surviving winter is to wait it out as an egg. The egg will hatch later in the year into a caterpillar so the egg must be placed on a plant the caterpillars can eat. The brown hairstreak is one butterfly that employs this strategy. The adults are hard to see as they fly high in the treetops and hedges, so counting eggs in winter on blackthorn is one of the most reliable ways of estimating their population.
Getting out of here
Two species of butterfly that spend their summer in Britain have a different way of coping with winter. The painted lady, and in lesser numbers the clouded yellow, simply head south to warmer weather in late autumn, generally reappearing around March. Where they went remained a mystery until fairly recently when researchers showed that the painted lady flies at high altitude all the way to sub-Saharan Africa. Next time you see one of these butterflies remember it will have likely flown over 1,000 miles to reach our shores.
