I wasn’t in the UK for the last huge influx of Painted ladies (Vanessa cardui) in the spring of 2009, when an estimated 11 million butterflies arrived here (Life Cycles of British & Irish Butterflies, p.241) but, in the last couple of weeks of April this year, we experienced a much smaller influx of this amazing migrating species.

This type of influx is subject to weather conditions; the butterflies take advantage of strong southerly winds to fly from sub-Saharan Africa across the Saharan Desert and the Mediterranean Sea to southern Europe and then onwards to more northerly locations, including Britain. (These weather conditions also see an increase in migrant moths arriving in southern Britain, in car owners reporting a thin covering of Saharan dust on their vehicles, and, sometimes, in murky skies and spectacular sunsets.)

I spotted my first two Painted ladies of the year at Cosmeston Lakes Country Park on 30 April, my bumper day of new sightings, as described in my last two blogs. ‘Nice’, I thought, and didn’t really expect to see a lot more, though I did notice reports on social media of large numbers of sightings across southern England.

Then, last Saturday, 2 May, as I walked the paths through the various fields at Cosmeston, Painted ladies just kept on appearing, as if by magic. My personal count after a couple of hours was 16, though I didn’t cover all the tracks around the park and I’m fairly sure there were many more I didn’t see. This number was certainly higher than I’d ever seen in one day before.

And you might be wondering what happens to all these butterflies? Well, according to Life Cycles of British & Irish Butterflies, research has shown that they breed here in Britain and their offspring migrate south again in the autumn. It’s estimated that, in the spectacular influx of 2009, as many as 21 million Painted ladies embarked on the return journey to Africa. Just incredible!