Please Flutter By

Not too long ago, we were chatting at eschaton about the missing fireflies that used to be everywhere after dark in the south when it was warm. Now it's rare we see them, and to see a whole field occupied by those little lightning blinks is almost unheard of. Partly we have all those lush green lawns requiring loads of insecticide to blame, I suspect, but what about climate change as well? Today I came across an article on butterflies disappearing from England that may apply to our disappearing natural world in the U.S. as well.

I began a less than scientific monitoring of butterflies in a little notepad when I was eight, helping my dad count the tiny brown argus on the Norfolk coast where we spent our summer holidays. Finding this darting, chocolate-brown gem ignited an awkward passion for butterflies that I kept well hidden during my teenage years. Dad and I would go on expeditions to discover, and photograph, rare species: we would sit in a wet meadow in Cumbria waiting for the marsh fritillary to emerge, or hover by piles of horse manure in the woodlands of Surrey, hoping the majestic, haughty (and turd-loving) purple emperor would descend from the treetops for us. Twenty years on, some of the nature reserves we visited have lost their precious rarities. If trends continue, another couple of bad summers could kill off some species for ever.

Numbers of the delicate wood white were down by 66% last year on dismal 2007; its population has slumped by 90% over the long-term recording period. The duke of burgundy and the high brown fritillary are most at risk of extinction. The high brown survives in just 50 small sites: at one spot in Dartmoor, there were 7,200 in 1995; last year, there were just 87. Nationwide, numbers have fallen by 85% over 10 years. "This run of bad weather has really pushed those species to the brink in many areas," says Martin Warren, the chief executive of Butterfly Conservation.

Wood white butterfly. Photograph: Peter Eeles Butterflies find it difficult to fly, feed and mate in bad weather but these figures are not just a seasonal blip caused by freakishly soggy summers. The collecting of British butterflies has ceased to be acceptable and yet butterfly populations have still plummeted. Far more devastating than unscrupulous collectors of old has been industrial agriculture and the loss of 97% of England's natural grassland and wildflower meadows; planting conifers or letting our broadleaved woodlands become too overgrown for woodland flowers; and the sprawl of motorways and urban development.

To this deadly cocktail has been added a new poison: climate change. In theory, a gentle global warming should benefit almost all of Britain's butterflies. Creatures of sunshine, most of our butterflies are found in southern England where many are at the limit of their natural range; as our summers become hotter, these butterflies should thrive and spread further north. There are a few winners already: the beautiful comma is moving north and the rare silver-spotted skipper has done well thanks to hotter summers. Britain may also be visited more regularly by exotic species that were once rare migrants.

A painted lady butterfly. Photograph: The Linnean Society of London The fate of one much-loved native shows that this happy outcome, however, will not come to pass for most species. The small tortoiseshell is the labrador of the butterfly world: cheerful and content to live close to humans. Its caterpillars devour ubiquitous nettles. As an adult butterfly, it feasts on suburban flowers and hibernates in garden sheds, pitter-pattering against our windows when spring comes round again. Thanks to climate change, it is spreading north and is now seen for the first time in remote parts of Scotland. Unfortunately, so too is Sturmia bella (how the person who named this ugly brute could call it beautiful is beyond me), a species of parasitic fly.

This nasty fly was recorded for the first time in Britain in Hampshire 11 years ago. By last summer, it had reached Merseyside thanks to a modus operandi every bit as gory as the Alien films. It lays its microscopic eggs on patches of nettles where small tortoiseshell caterpillars feed. These unwittingly eat the fly's eggs which become tiny worms inside the caterpillar, bursting out of their bodies just when the small tortoiseshell is beginning its miraculous transformation into a butterfly inside its chrysalis.

Last year was the worst ever year for small tortoiseshells, its population slumping by 45% compared with 2007, despite thousands of migrant small tortoiseshells arriving from Europe in September.

Those swarms of migrating monarchs that used to pass through my lawn haven't just taken a detour, it seems. We spray them, and we run their water supplies through the rinse cycle and our lush green lawn sprinklers, and we destroy their climate with our insistence on our own comfort.

It's probable that all of us reading this post, though, take a lot of precautions against damaging the world around us since we are concerned enough to inform ourselves and act responsibly. Sadly, that category of 'us' isn't large enough to make the difference. Our climate change is taking its toll on fellow creatures, and we have to be active to make the changes in all our lives if we're going to save the beauties of the universe.

Today I'm in Sicily, and it's overcast. I wonder if I'll see a butterfly at all. If I do, I'll be very glad. But whether I do or not, I do see that our activism is going to be increasingly important to that butterfly and its fellows.