Look out for the purple emperors this weekend
If you want to see the largest and most exotic butterfly in Britain this is the week. Purple emperors have been known to emerge in late June but July 4 is the date I have always looked for them. Having emerged from their chrysalis cases on willow trees in the first week of July they often come straight into the garden to find trace elements of chemicals needed to strengthen themselves.
My photograph, taken one year, shows a female purple emperor which settled on my wife’s hand and dabbed at scent of soap, body chemicals, or whatever it thought it needed as a pick-me-up. This close encounter has occurred many times over the past 50 years usually on the first day the butterfly emerges. Then having filled up with whatever it wanted it disappears to the tops of the oak trees and does not come down again for the next three weeks as it meets up with others of the tribe when they sort out their mating requirements after which their lives are over. The same oak tree is used year after year for these nuptials. Across southern England there are other such landmark oaks that may have been used for centuries.
Both male and female have appeared on our lawn. One year in the 1970s there were half-a-dozen of them on the July 4 or thereabouts, dabbing at all kinds of unlikely chemicals from creosote and oil to insects squashed on the front of my old Alvis car. They are always known to like a bit of pheasant or deer poo and collectors of old even collected up horse manure to entice the insect down to ground level.
This butterfly season here so far has been such a wash-out, and we wonder if any emperors have survived. All species in the spring were in very low numbers and many such as brimstone and orangetip, green-veined white and large white hardly appeared at all. There were one or two violent hail-storms and gales of rain which did not help those butterflies as they looked for mates. Sudden warm days helped the unusual rarities such as
grizzled skipper and dingy skipper. Some of these clung on to life for a month as they hoped to meet up with partners. We saw them on the hot fine days after they had been hiding up for a week in wet weather.
Even the old stalwarts of the countryside such as peacocks and red admirals were finished off by spells of miserable weather. But I was pleased to see one red admiral and one comma which had survived the winter in hibernation, looking very chirpy at last at the end of May as they laid their eggs on nettles in the garden.
During the 47 years I carried out my weekly butterfly count at Kingley Vale my research showed regular good years followed by bad years, on a seven-year cycle. We must be in one of those troughs this year. But it is not over yet and for most species it is just beginning with meadow browns, ringlets, marbled whites, large and small skippers and silver-washed fritillaries among them.
Will the purple emperor appear this year? It has so far never failed, though the numbers have decreased. I shall be keeping my eyes on the skies for the next fortnight and my wife will be holding out her hand if ever she has time to get away from her work of typing up my current books on her computer.