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If you go down to the woods today.......


Most people want to see the Purple Emperor on the ground. This is a typical pose of the species with its wings open and ibibing on stony ground getting nutrients up its proboscis . Most of the time you very rarely see the Purple Sheen on both wings, its either the left or the right. You have to be standing right over the butterfly and normally its better on overcast days.


Dog walkers to me should always clean up after their dog has done its business, but on the odd occasion during the summer they can be quite forgiven when they leave a deposit on the ground which invariably will attract the butterflies like Commas Red Admirals, but none more so than his Imperial majesty, which will sit on the dog poo for many minutes giving you a good viewing of this gracious insect.

The original Bag of Delight- Purple Empe

Over the years I have managed to attract the Purple Emperor on to my camera bag, where it has stayed enjoying whatever it can find for up to an hour or so. Maybe its transfixed by the colour which it is very similar to its wings?


Is it a Purple Emperor or a Royal Blue Emperor I have lots of photos showing a more blue colour but depending on the light, shade and angle you see the wings, it can be Purple as the name suggests.


When out looking in the woods look for bleeding oaks with a substantial sap run, which have been struck by lightning or have been attacked by other forces like the wind or just rotten by age. Here the smell can be quite potent and the Purple Emperor will likely seek this out and imbibe on the sap for many minutes. Some sap runs can be away from you eyesight, and the purple Emperor can be seen sometimes flying well into the bough of the tree, and disappearing for minutes at a time.

Victorians used to drill large holes in the bark of the tree to encourage sap runs and hence get their prize the Purple Emperor, this used to take place in the New Forest and Alice Holt Forest to name a few.


A typical ride in a Purple Emperor wood with wide vistas looking towards the crowns of the Oaks. This is the kind of vista to look for when the Emperor is Oak edging and Sallow searching in the morning.

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Another typical woodland ride where you would encounter the Purple Emperor, this is Whiteley Pastures and Botley Wood near Fareham in Hampshire.

Purple Emperor: The butterfly that feeds on rotting flesh

By Emma Ailes
BBC News


23 July 2015



For a few weeks in July, groups of people can be found wandering English woods carrying strange produce - including rotting fish, Stinking Bishop cheese and dirty nappies. They're out to bait the Purple Emperor, one of Britain's most elusive butterflies, whose beauty disguises some filthy feeding habits.

You never forget your first time, says butterfly enthusiast Neil Hulme.

"My dad and I were walking through the woods, and we came across a woman in her 30s wearing stars-and-stripes trousers, bent over. Some men in tweed with cameras and long lenses were photographing her from behind."

He moved closer and realised they were taking pictures of a Purple Emperor butterfly that had landed on her bottom.

Hulme was transfixed by the creature - especially when it fluttered up and landed on his collar.



"The butterfly paparazzi moved in and surrounded me," he recalls. "In blind optimism I held out my hand as a falconer might, and it landed on my finger. It was such an amazing experience. I was hooked."

So began a decades-long love affair, which has seen him devote almost every second of every summer to the pursuit of this mysterious butterfly. Now is the key time of year - by the end of July, all of the Purple Emperors will be dead.

Hulme's purple passion runs so deep, he gave his daughter the middle name Iris after its Latin name, Apatura iris.

media caption Purple Emperor fan Neil Hulme: "It's a violent thug with the filthiest table habits imaginable."
























The Purple Emperor is rare among butterflies. It avoids flowers, preferring rotting animal corpses, faeces, mud puddles - and even human sweat.

It dwells high in the tree tops in the domain of birds. The males, who boast the deep purple iridescence, spend their brief lives "drunk on oak sap, brawling in mid-air battles and chasing down virgin females", says Hulme.

"It's a violent thug. It attacks anything that comes into its airspace - it even tries to chase big birds like buzzards. It has filthy table manners."

The strange behaviour of "His Majesty" - as the Emperor is affectionately known - inspires equally unusual behaviour in people.

At Knepp Castle estate in West Sussex, people carrying huge cameras and binoculars can be seen dotted across the landscape.

Trotting down one woodland path is 71-year-old Hazel Land, a dainty woman in a large straw hat and sunglasses. She's travelled some four hours from Devon in search of the Purple Emperor.

From her pocket she produces a lump of ripe Stinking Bishop cheese, lightly wrapped in cling film. "It really smells - want a whiff?" she offers. "It's my bait. I swear by it. And you can always have some for lunch."



She admits the Emperor's seem to be off cheese that morning - but she passes on some intelligence about a female spotted on a bramble bush not far away.

Hulme, who now works for the charity Butterfly Conservation, has brought his own secret recipe - a foul-smelling Indonesian shrimp paste called Belachan, which he mixes with hot water and spreads on woodland paths. Sometimes he adds pickled mudfish.

People try "all sorts of ridiculous things" to bait Purple Emperors to the ground for a much coveted shot of its resplendent wings, he says. That includes roadkill, dog poo, rotting fish and even babies' nappies. It's thought the butterflies are attracted to the salts and minerals.























"My friend Matthew once hoisted a 15lb (7kg) salmon into the top of a tree," says Hulme.

"Urine-soaked fox scat [dung] is one of the most attractive baits there is to the Purple Emperor. I know of people who go out first thing and scoop them into a bucket.

"And there's a very good fish paste called Shito from Ghana - although I haven't managed to get hold of that for a couple of years now."

In Bentley Wood, Hampshire, people traditionally hang rotten banana skins - although Hulme is dubious about their effectiveness.


One clergyman, the Reverend Prebendary John Woolmer, who has a letter on the state of the Purple Emperor published annually in the Times, even calls on the power of prayer.

He conducts a woodland service at the beginning of each Purple Emperor season in Northamptonshire to bless the forest rides. His purple stole is embroidered with butterflies.

But while unusual, the tactics of these butterfly chasers are nothing new. The tradition of baiting Purple Emperors goes back at least 250 years.


In Victorian times, the heyday of butterfly collecting, gamekeepers would attract Purple Emperors down to their gibbets by hanging out rotting carcasses of crows and rabbits.

In the early 20th Century, expert lepidopterist and Purple Emperor obsessive IRP Heslop imported a trailer-load of pig manure for bait, and designed a 37ft (11m) net for scooping them from the tree tops.

More recently, people have tried cherry-picker cranes to access the canopy, or even floating purple helium balloons or hurling clods of mud into the air to provoke them into the open.























Hulme has ideas for sending up miniature kites or a drone - although the blades would have to be protected. "We wouldn't want to see one shredded."

Back in Knepp, another hunter, Paul Fosterjohn, is lying flat on his back - "the best Purple Emperor spotting position" - under a tall oak tree.

A 25-foot ladder is precariously secured with his belt to a mid-level branch that's oozing sap - a Purple Emperor delicacy. At the sight of one, Paul scampers up the ladder for a closer look and a photo, before diligently noting down every detail.


He has spent much of the last two weeks in this manner. "I'm mostly interested in birds, particularly cuckoos, but there's something about the Purple Emperor. I don't know, it takes you back to being a child again."

Fosterjohn is still childlike in his captivation at every new sighting. At one point he spots a pair tumbling in a downwards spiral in the distance.

"It's a male-female rejection," he yells and begins leaping over brambles and ditches towards them.

Matthew Oates, who hoisted the salmon, author of In Pursuit of Butterflies, is the UK's leading Purple Emperor expert, and has dedicated 45 years to trying to understand them.

In previous years, he's held foul-smelling "butterfly banquets" on trestle tables in the woods, with plates of rotten shrimp and fermenting jellyfish slices to bait the insects.


He says only now are some of the mysteries surrounding this butterfly beginning to unravel. "A lot of knowledge about the Purple Emperor was assumption and mythology - there are huge areas about its ecology and other dimensions we don't know about," he says.

"For example, it was always thought they were dependent on ancient oak woodland. In fact the caterpillars feed on sallow - or pussy willow - thicket."

Sallow was traditionally seen by foresters as a weed, and rooted out.




But at Knepp, a "re-wilding" project by estate owner Charlie Burrell to allow parts of the land to return to its natural pre-agricultural state has allowed sallow habitat to develop over the last 15 years.

A boom in Purple Emperors has ensued, this year overtaking even famous hotspot Fermyn Woods in Northamptonshire for sightings. It could mark a huge step for conservation.

By August, the last of this year's Purple Emperors will die away. "You do feel sad when it's over for another year," says Hulme.

"Purple Emperors are this wonderful celebration of British summer. Matthew likes to say they just fly away into the sunset. It's nice to think about it like that."

'His Majesty'


  • The Purple Emperor was first defined as a species, Apatura iris, in 1758

  • It is one of the UK's largest butterflies, second only to the Swallowtail. It has a wing span of up to 8.4cm (3.3in)

  • The adult butterfly emerges in early July, with peaks in the second and third weeks of July. It is mostly found in woodland in central southern England

  • Its elusive nature makes it difficult to establish how many Purple Emperors there are in the UK, but it is considered a species of conservation concern


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Purple Emperor baiting.jpg

BBC TV crews on Countryfile hold their breath in a wood in Northamptonshire waiting for any sign of the Purple Emperor to come to the table to feast in front of the cameras.

There are all sorts of baiting techniques with all sorts of foodstuffs, most coming from exotic markets in Thailand. However good old Tuna can work if left long enough to 'ripen' as it were.

Neil Hulme puts down some of his fishy grog on a ride in a well known wood. Belichan is a recipe he only knows how to make and attract his majesty. Many have tried and failed....


The mornings should be spent looking up at the Oak crowns to see the male Purple Emperor flying in and out of the sprigs of leaves and over the tops of the crowns going one way down a ride then back down the other side, looking for potential females. Later on they will start to hunt in and around good Sallow stands, and then around about mid-day towards one o'clock in the afternoon they will have made there way up to a Assembly point to fend off other males in the areas, establish a territory and flex their muscles, hoping a potential female has been looking on, and courtship may start .

Typical ride in Havant Thicket with good

A typical ride in a Hampshire wood, this is Havant Thicket, and this ride is over a mile long, and several males in a good year could be encountered along a ride like this following the contours of the Oak stands.

Purple Emperor male 8.jpg

Despite there size and colouration, on the ground the Purple Emperor is still a hard insect to detect, unless you have seen it land in front of you, and it starts to wing wave and imbibe on the ground then they will be quite jittery, and will not let you get very close, but a major feed on fox droppings or other unsavoury items on the ground then your in for a treat....

Purple Emperor caterpillars on

The Purple Emperor caterpillar is a beautiful animal perfectly camouflaged against a sallow leaf,although Blue Tits in the spring have the potential to devastate populations in the canopy and the Purple Emperor numbers can be very low in some years.

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The Pussy Willow, Sallow 'Caprea' is the main food plant of the Purple Emperor caterpillar in woodland and along hedgerows, river and wet meadows. Matthew Oates has calculated that a good Purple Emperor wood needs at least 400 of these trees of different ages,and particularly the female variety which have the furry underside, just one of the needs to hold a good population of the Purple Emperor. In my experience walking around a lot of woods in Hampshire there is nowhere near that number. Although the Female Purple Emperor will lay on the narrower leafed Sallow, and other hybrids inits effort to lay her eggs.

Female Purple Emperor on Buddleia.jpg

Just like my 'other' species the Duke of Burgundy the Purple Emperor is not renown for feeding off of flowers, but occasionally they will buck that trend. I have seen amale on Bramble before in Goose Green Inclosure. Females are often seen on Buddleia, this may well be that it's another source of vitamins for the egg-laying process.

Purple emperor butterfly guide: how to identify, what they eat, and when and where to see them


Sometimes referred to as ‘His Imperial Majesty’, the purple emperor is an impressive but elusive butterfly. Learn more about this species in our expert guide by Matthew Oates.

By Matthew Oates


With iridescent purple wings on the males, and as one of the UK’s largest butterfly species, the purple emperor is a much sought-after species by nature lovers. However, it’s surprisingly elusive and has some unusual tastes. Discover more in our expert guide by naturalist and author Matthew Oates.


Where are purple emperor butterflies found?


The purple emperor is found in and around woodland in much of central southern, south east and eastern England, and can be anticipated in parts of the West Country, the western Midlands and eastern Wales.

Abroad, it is a species of the middle band of Europe, avoiding the hottest and coolest regions.


Two other species of emperor butterfly occur in Europe, the lesser purple emperor and Fryer’s purple emperor. In both, the males possess a golden sheen over the purple iridescence.  Further east, other Emperor species occur, some without any purple.


What is the scientific name of the purple emperor butterfly?


This butterfly trades under the scientific name of Apatura iris. It is the only species in the Apatura genus in the UK.

‘Apatura’ (Greek) has something to do with deception, referring to the male’s deceptive purple iridescence, seen only from certain angles. Iris was the winged messenger of the Roman gods, who appeared in the guise of a rainbow and was a demi-god in her own right.


How to identify a purple emperor butterflies


In the UK, the purple emperor is quite distinctive. It is the size of a small bird or bat, is a powerful flyer, and tends to glide and soar high up around medium-sized trees. Seen from below, it appears as a black butterfly with distinctive white bands and spots.

The purple emperor has black wings, but when caught at the right angle, the males’ upper wings have a rich and iridescent blue-purple colouration. Females can look similar to white admiral butterflies, but have an orange-ringed eyespot.


The white admiral is similar, but is much smaller, flits rather than soars, and tends to fly much lower. The upper wings are brown-black in colouration, with a white band colour and no purple.  If in any doubt, it’s not an emperor: the purple emperor leaves you in no doubt.


How to identify purple emperor caterpillars and pupae


Purple emperor caterpillars go through five instars before pupating, developing two horns on their head in the second instar. They hibernate over winter in their third instar form, and recommence feeding on sallow in spring.

When fully grown, the caterpillars will leave their feeding site and travel, sometimes to the top of the sallow tree, to pupate.


The pupa is between 3o t0 35mm in length, and matches the green of the sallow leaves, darkening slightly before the butterfly emerges in summer.


When is the flight season of purple emperor butterflies?


The flight season lasts about six weeks, though numbers are low for the last three. Traditionally, the purple emperor season started in early July, peaked mid-month and petered out in early August, though there were always early years, like 1976, when it started in late June.

Now, with climate change, the season starts in mid-June, peaks in late June or early July, and is finished by August.  We may even get a partial second brood in the autumn.


How numerous are purple emperor butterflies?


For the last hundred years, populations have been so low that we decided that this is by nature a scarce insect which only occurs at low population level. That’s nonsense, it can occur in fair numbers, though not (yet) in the abundance of some of our blue and brown butterflies.

At Knepp Wildland in West Sussex, it is relatively numerous, such that well over a hundred individuals can be seen in a day, by those who know how to look.

Crucially, the techniques for spotting purple emperors are unique: you look up, around the trees, and never look for them around flowers, which they seldom if ever visit. Birders are particularly good at spotting emperors.


What do purple emperor butterflies eat?


Female purple emperor butterflies lay their eggs on the upper sides of sallow and willow leaves, usually in fairly shady situations. These hatch after two to three weeks.

The insect then spends ten months in the larval state, five of them in hibernation on twigs, usually in forks or by buds. Larvae feed very slowly before hibernation, but rapidly during May. They usually wander far before pupating, spending some three weeks as pupae.

The adults rarely visit flowers. Instead, like many tropical butterflies, they imbibe minerals from the woodland floor, from sap runs on oak trees, and sometimes from honeydew (the sticky secretion of aphids on leaves).


Victorian butterfly collectors used to bait them down, with dead rabbits or worse, but today they descend to feed on indelicacies such as fox poo and worse, dog muck.


Two male purple emperor butterflies feeding on fox scat. © Matthew Oates/Neil Hulme

What eats purple emperor butterflies?

We don’t rightly know. The hibernating caterpillars are mercilessly predated, probably by tits. Pupating larvae and pupae also suffer high levels of predation, but we don’t know the details.

The adults are fairly predator-proof, and will readily attack birds (small, medium and large – as big as red kite and grey heron). Unfortunately, the males are so inquisitive and fearless that they get squashed on roads or mashed up in cement mixers!


Are purple emperor butterflies endangered?


The purple emperor butterfly went through a period of decline during the 20th century, due primarily to foresters regarding sallow bushes as obnoxious weeds, and cutting them down.

That prejudice is still a problem locally, but sallows are now generally regarded as great for biodiversity, and are allowed to grow in quiet corners.


Climate change may pose a new, greater set of problems, particularly in the form of mild winters which make proper hibernation (or diapause) difficult.

Atmospheric nitrogen deposition may present further problems, rendering sallow foliage unsuitable.


What work is being done to help purple emperor butterflies?


Above all, this butterfly needs understanding, and appreciating. Hopefully, my book, His Imperial Majesty: A Natural History of the Purple Emperor, will help give it the glorious future it deserves.

On the most basic level, it simply needs sallow trees – the more, the better. Its needs can be variously met, and it doesn’t have challenging conservation requirements. This is one butterfly we can quite easily ‘save’.


Where are the best places to see purple emperors in the UK?


At the moment, there are strong populations in Fermyn Woods (Forestry England), west of Brigstock in East Northants, Bentley Wood on the Wiltshire and Hampshire border, and on the Knepp Castle Estate (private, with limited access) in West Sussex.

Other sizeable populations are developing, notably in the new Heart of England Forest in Warwickshire. These are Super League populations.

Mostly, the butterfly occurs in modest numbers in most of the larger woodland systems in southern counties.  It is also being discovered in suburbia, with colonies on Hampstead Heath and in Richmond Park. It’s on the march – a good news story!


His Imperial Majesty: A Natural History of the Purple Emperor by Matthew Oates is published in hardback by Bloomsbury Wildlife.



Knepp Wildland.jpg

The future of wildlife and especially rarer flora and fauna can be seen at the fantastic Knepp Wildlands in West Sussex,I know its not Hampshire, but I think in the next 10-20 years we will have sites like this in practically every county. Knepp has the possibly the largest population of Purple Emperors anywhere in the world, which is a pretty bold statement. 

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