March 2019 (Painted Lady, Kershaw)

Last month I wrote about how similar the Australian painted lady butterfly is to the UK painted lady, and how puzzled I was about how there came to be two very similar but distinct species.  It turns out that the painted lady butterflies that we get in the UK (Vanessa cardui) is not confined to Europe and North Africa, but can be found on every continent except Antarctica and South America.  This is probably due to their exceptional migration capabilities – they migrate from North Africa, through Europe and the UK and end up near the Arctic Circle, from where in autumn, they migrate back to N. Africa, a distance of about 9,000 miles. 

UK Painted Lady - Vanessa cardui

This degree of mobility means that Australia has had painted lady butterflies probably about as long as painted lady butterflies have existed. Opinions on when butterflies evolved vary from 40 million years ago, to 140 million years ago, but their evolution probably coincided with the spread of flowering plants during the Cretaceous period (79 – 145 million years ago).  There is still a population of ‘UK’ painted lady butterflies (V. cardui) in Western Australia around Perth, whereas the Australian version (V. kershawi) can be found over most of the Eastern half of the continent and must have evolved from an original population of V. cardui.  The genitalia of the Australian adult male butterflies are significantly different to that of the European males so that it is now considered a different species.  It is unclear what caused the change, but evolution of nectar feeding insects can be affected by the availability of suitable forage plants.

Australian Painted Lady - Vanessa kershawi

As a footnote to this tale, I was intrigued by the reference to Kershaw in the scientific name.  It turns out that William Kershaw was a 19th century naturalist and gold prospector who had a passion for collecting moths, butterflies and beetles. His meticulous collection came to the attention of Frederick McCoy at Melbourne Museum, who purchased the collection and employed Kershaw at the museum.  They became great friends and when McCoy described the painted lady in 1868, he dedicated the species to his friend William Kershaw.

It was good to get back home after our Australian trip, even though the weather was cold, dull and wet for a few days. But we’ve had a week of mostly sunshine since then so that we can get out and see some of the early signs of nature coming back to life as winter loses its bite.  It was nice to see the familiar birds at the bird feeders – not as brash and colourful or noisy as the Australian birds but just as beautiful in their own right.  I thought that I caught a glimpse of a brambling but it may well have been a slightly scruffy chaffinch.  Brambling are one of a number of species that migrate to the UK when their food sources run out in Scandinavia.  This year there has been a shortage of beech mast which is normally reliable and long-lasting forage for the bramblings.  They normally feed in small flocks, which makes the solitary bird that I saw even less likely to have been a brambling.  Other Scandinavian species that we may see trying their luck over here are redwings, fieldfares and waxwings.  We had waxwings at Pett Level a few years ago, though I didn’t get to see them.

It was good to see snowdrops in the garden when we got back. 

We have now managed to increase our one solitary clump and now have 4 clumps of them, though clump is perhaps not the right word to use for the two that have only one flower each.  Pett village seems to be bursting into flower early this year with several verges putting on a good show of crocuses.  Not long to wait now before we hear the first lawnmower of Spring.