Many of us are familiar with that butterfly lifecycle diagram, the circle with arrows showing the four stages of development from egg to caterpillar to adult. Perhaps you had to draw it in primary school. It’s a lovely clear representation, but it doesn’t explain one key element: the cycle doesn’t start at the same time of year for every species.
In Britain, most butterfly species spend the winter as caterpillars, curled up at the base of their foodplant waiting for spring’s fresh new growth. The majority of the rest are either tiny eggs or camouflaged pupae all winter, trying not to become a mini snack for a hungry bird or mouse.
Just 5 of our resident 57 species of butterfly spend the winter as a fully formed adult. Looking much like a dried leaf, they stay dormant (semi-hibernating) deep in hedges, wood piles or holes in trees, hidden in tussocks of old grass, or in garden sheds, barns and garages, sometimes in huddles of quite a large number, perhaps even with other species of butterfly or moth. There they’ll stay until a spring day that’s warm enough to wake them, when spreading their wings they will head off in search of a mate. The first eggs are usually laid in April and the cycle starts all over again.
We see all these 5 at Sun Rising. Often the first is the Brimstone; it’s the males’ rich yellow colour that may be why butterflies are called butterflies. However, this year it was the Peacock that emerged first, probably disturbed when we were moving bags of tree mulch. The other three are the Small Tortoiseshell, Comma and Red Admiral. Often an adult emerging in spring is a little tatty. You can see this Peacock, trying to warm itself on the stone track, has lost some of its wing colour.
The mild wet winter is not kind on butterflies, wherever they are in the cycle. Just as for us humans, mild winters lead to more problems with pathogens, like bacteria and viruses. For the five who overwinter as adults, the higher temperatures can also raise their metabolism, meaning they use more energy through the winter, emerging in a weaker state. It is even more important to have those early nectar-full plants available for them to feed on. If you find an adult who is clearly struggling, it may appreciate a little sugar water (dissolve sugar or honey in hot water, allow it to cool and then use a cotton pad that will soak up the solution and give the butterfly something to stand on). After this very mild wet winter, let’s be sure to celebrate all the butterflies we see emerge!