By Sarah Jones
"You don't get this butterfly served up to you on a plate. You have to go out and look for it."
The purple emperor is one of the rarest, most elusive and most beautiful of the UK's butterflies.
The size of a small bat, fearless and aggressive it's a butterfly that has inspired legions of followers of "the purple persuasion" to travel miles in the hope of catching a glimpse of it.
And the Savernake Forest is one of the very few hunting grounds in the country where this "connoisseurs butterfly" can actually be seen.
For Matthew Oates, a nature conservation adviser to the National Trust, not only is the purple emperor Britain's unofficial 'national butterfly' but 'purple emperor-ing' is actually a verb or more accurately an obsession.
Not only is he breaking new ground into the secret life of "His Majesty" but last summer spent three months cycling around Savernake hunting down and cataloguing hundreds of tiny emperor caterpillars hidden in the forest's sallow trees.
So what is the attraction of this large and eccentric butterfly?
We caught up with Matthew in the Savernake Forest to find out more about Wiltshire's magnificent purple emperor:
"I saw my first purple emperor on the 5th of July 1970 and that moment changed my life and so I've been in pursuit of the purple emperor for over 40 years now.
"It's like no other butterfly. It is immensely beautiful and wonderful yet it is eccentric.
"You will not see this butterfly on buddleia bushes. You won't really see it in your garden.
"I saw my first purple emperor in 1970 and that moment changed my life"
"Seeing a purple emperor is like seeing an osprey plucking a fish from the surface of a loch. It's that big.
"But it's not easy to see. It is a connoisseur's butterfly. You don't get this butterfly served up to you on a plate. You have to go out and look for it.
"If you see one you will not mistake it and you will not forget it.
"You're talking about an insect that's the size of a small bat.
"Their wing span is over three inches and the males have this magnificent purple iridescence which can only be seen at certain angles and that purple will change with the angle you're looking at it.
"It can be anything from bright, azure, iridescent, electric blue through to royal blue on to a really spectacular deep purple.
"They can fly at great speed and are capable of doing anything. They are highly inquisitive and extremely aggressive.
"I have been hit in the eye twice by a male purple emperor and on the first occasion it almost knocked me out.
"I've even seen them chase red kite, buzzard and heron.
"When males establish territories, where they wait for females to come up in need of their attention, they're very worked up and full of testosterone, so that anything that flies through that territory they are going to pursue be it another insect or be it a bird and yes even a heron.
Fox poo and fish bait
"They feed on honeydew, the sticky secretions aphids leave behind on leaves.
"I've got rather attached to my overwintering caterpillars"
"But once in a blue moon the males will come down and settle on the ground.
"They don't visit flowers instead they tend to drink rather nasty juices from the woodland floor and the old butterfly collectors used to exploit that and put out dead rabbits.
"Nowadays it's mostly things like dog poo and fox poo which they go on.
"But frankly nothing is better then fresh fox poo.
"Saying that the emperor does rather enjoy fishy smells and I did actually haul a 20 lb salmon up into a tree, 30 feet up, and incredibly about 18 months later it was still there.
"I wonder what people thought of it?.
Byron the caterpillar
"I was on sabbatical from the National Trust, last summer, for three months and I spent 10 days doing an absolute search of every bit of sallow in Savernake I could get to and I found 141 emperor caterpillars scattered almost throughout the whole forest.
"But at the moment there are only 17 still known to have survived. It's terribly high losses.
"As a biologist, I should have given them numbers but as a great fan of English verse I named them all after poets.
"And I rather regret it as there's been quite high predation. There was an appalling time when T. S. Elliot got eaten and I lost Dylan Thomas but yes I did regret having done that. It's been really stressful losing as many as I have.
"It is scary. I've got rather attached to my overwintering caterpillars, which is most unprofessional, and yes I've been traumatised by it."
How to see them
Purple Emperors are at their best on sunny days from mid-summer through to the end of July when they can be watched by scanning the tree tops with binoculars.
The best places in Wiltshire to see them include Bentley Wood in South Wiltshire and around the Ailesbury Column in the Savernake Forest where a colony is known to exist.
For more information click on the link:
The Purple Empire