Wildlife Column with Prof Ian Rotherham
So far this year has been a bit of a mixed bag for butterflies, though the widespread tendency to relax mowing regimes on roadsides will undoubtedly bring some benefits.
For some species however, it will take a few years for the wildflowers and associated butterflies to really bounce back. In the meantime, a critical factor for the more common butterflies is weather. Sadly, the state of the most visible butterflies doesn’t really reflect the longer-term declines of many species due to bad land-use and over-intensive farming and similar. That said however, for most people it is these obvious and large butterflies known as the ‘vanessids’ which are most commonly seen and therefore important to people. Here we are talking of species like the peacock, the red admiral, the comma, and the small tortoiseshell. All of these breed with us and some over-winter; however, some migrate to Britain from warmer climes. Perhaps of the latter, the most spectacular and indeed familiar, is the glorious ‘painted lady’; clouds of which can sometimes be picked up on satellite imagery as they move in thousands or tens of thousands from North Africa across to Europe. These are big (for a butterfly) and are powerful fliers. They swarm in numbers across southern Europe and may then cross the Channel or the North Sea to get here. Once here they feed and breed and find thistles and burdocks as favoured food-plants, but the adults will feed on knapweeds, buddleia, valerian, marjoram, and many other garden flowers too. Unlike some of their cousins, the painted lady caterpillars can feed on a wide variety of plants.
This is our most obviously spectacular long-distance migrant butterfly and hot July weather triggered a big invasion with further breeding once they arrived here. So this is truly a ‘painted lady summer’. At present they generally can’t survive our winter weather although a few may over-winter in southern England. With climate change this may all change. At present, it seems that some of our butterflies, perhaps ones raised here, make a return migration in the autumn.
Professor Ian D. Rotherham, of Sheffield Hallam University, researcher, writer and broadcaster on wildlife and environmental issues