Purple Reign - The Emperor Returns to Woods Mill

By Michael Blencowe

People & Wildlife Officer

In any book on British butterflies you’ll find our 58 species segregated into social ranks; the common browns, the blue-collar blues, the working-class whites. But keep turning the pages, past the lepidopteral lower-classes, and you’ll find a butterfly so unique, so magnificently majestic, so breathtakingly beautiful that for centuries British naturalists have bowed before it. Draped in resplendent robes of iridescent amethyst, obsidian and ermine the purple emperor has to be one of the most impressive animals on our island.

Aside from an alluring appearance emperors also possess that combination of rarity and elusiveness which has elevated them into an almost mythological figure; a butterfly bigfoot. How a large, shiny purple butterfly manages to exist undetected in our countryside is down to an arboreal existence. Purple emperors spend almost all their time on lofty thrones high above our woodlands. If we’re lucky we may glimpse the glide of a wide-winged silhouette as we stare sore-necked and squinting at the sycamore skyline.

Up there, in their canopy kingdom, emperors compete in a power struggle for territory and males gather for summer tree-top tournaments. Their wings flash as they clash in acrobatic aerial jousting and they spar and spiral high into the Sussex skies. The emperor’s ferocity and fearlessness in the defence of his realm are famous. Butterflies, bumblebees and other insects get a battering if they trespass and, incredibly, bemused birds (including woodpeckers, sparrowhawks, gulls and herons) also receive a warning wing-slap.

Emperors don’t lower themselves to feast on flowers like other butterfly riffraff. The emperor sups sugars by quaffing only the finest honeydew distilled by aphids in the treetops. Yet in complete contrast to its aristocratic high life the emperor has some dirty habits which drag him down to the filthy forest floor. To get his majesty’s mojo working he requires a mid-morning meal of minerals which he obtains by probing his proboscis into the most disgusting muck he can find. If you’re lucky (?) you may see him probing around on dog poo, used nappies, dead animals, sweaty feet – nothing is too repugnant. It’s like finding the Queen rummaging through the bins at the back of Tesco.

The female empress does not have the shining sheen or horrid habits of the emperor but she too descends to lower levels searching shady sallows for a place to lay her eggs. Camouflaged caterpillars munch from August to June before giving rise to another distinguished (but disgusting) dynasty next year.

On Saturday 11th July I ran a butterfly identification workshop at Woods Mill. After a illustrated i.d. lesson we headed out around the reserve to test our new knowledge. I was just pointing out the i.d. features of the meadow brown and gatekeeper when a large butterfly glided powerfully overhead and landed in a willow - a purple emperor. I had always had a feeling that emperors were here but had never found them. We headed to the oak which I had always optimistically called the 'purple emperor tree' and, lo and behold, found another sat waiting for us, peering down from the canopy. To my knowledge these are the first records from Woods Mill since the 1980's.

The purple emperor is an elusive butterfly but by no means rare in Sussex. There are hundreds of sites in this county where you can encounter an Emperor. They are currently more common in the west of the county but can be encountered as far east as Lewes and Wadhurst. If you find some goat willow (sallow) adjacent to some tall trees spend ten minutes staring at the tree-tops on a calm, sunny morning and you may be rewarded.

Purple emperor at Woods MIll (11th July 2015) Photo by Amy Tyler-Jones