How to spot hibernating butterflies this winter

Matthew Oates Specialist volunteer, butterflies

A hibernating Brimstone — Hibernating Brimstone

Associated with warm summer days, five of our common butterfly species spend the winter hibernating. Find out how to spot hibernating butterflies during the cold winter months.

Britain's hibernating butterflies

Five of our 59 resident species of butterfly spend the winter as hibernating butterflies, though few studies have been done as to precisely where and how they hibernate. These species enter hibernation unmated, and pair up in the spring.

Brimstone

The Brimstone usually hibernates amongst tangles of bramble or ivy in sheltered, sunny places. They emerge on the first days of spring sunshine, when the temperature reaches 13°C.

Comma

We don’t really know where the Comma hibernates, as very few of them have ever been caught in the act. They mimic dead leaves, which may be a clue. A few have been found amongst honeysuckle tangles and in coppiced hazel bushes but they are perhaps too cryptic to find.

Peacocks, Small Tortoiseshells and Red Admirals

The other three hibernating species seem to be associated with holes and hollows. Peacocks enter hollow trees, log piles and old rabbit holes. But along with Small Tortoiseshells and some Red Admirals, they also regularly hibernate in buildings. These three prefer unheated sheds, garages and attics, especially buildings which are dark, dingy and rather damp.

Where to find hibernating butterflies

Peacocks, Small Tortoiseshell and a few Red Admirals often choose cold, damp buildings and tunnels – also used by many bats.

World War II pill boxes have long been favoured, by both bats and butterflies, and also hibernating Herald moths. You can see Peacock butterflies hibernating in pill boxes on Studland Heath, Dorset.

How you can help

Central heating is disastrous to hibernating butterflies, as it causes them to desiccate – so if you find a butterfly hibernating in your house, rouse it gently and relocate it to the garden shed.

Away from our predator-free houses, hibernating butterflies remain vulnerable to predation by spiders and sparrows.