The Purple Emperors at Fermyn Woods - 11th July

Every July the Purple Emperors at Fermyn Woods in Northamptonshire put on a fantastic show as they flit majestically around the tree tops, occasionally heading down to the ground to feed where they provide excellent views for the many enthusiasts that have travelled to see them.

With reports of the Emperors emerging the weekend prior, I knew from past experience that the next weekend would be the perfect time to go as the butterflies would be at their best - later on in the season they tend to stay up in the trees more with the wings becoming slightly worn. Having seen Purple Emperors at Fermyn several years ago, but with Alex never having experienced the wonders of them for himself, we drove down to Northamptonshire to catch up with these most regal of butterflies.

Arriving on site after lunch, despite the majority of Purple Emperor activity usually being concentrated in the morning, we still managed an impressive number of individuals – around 15-20 in total - with many of these landing on the ground in front of us.

Usually found high up in the tree canopy feeding on aphid honeydew, Purple Emperors are well known for providing great views as they come down to the ground to feed on a variety of materials (often rancid smelling) to gain valuable salts and minerals. Favouring the edges of dips and puddles in the path, there are often a whole range of temptations brought by those looking to lure the Emperors down - bananas, shrimp paste and fox poo all seem to work well! The butterflies will also readily land on people (attracted by the sweat) and one actually landed on Alex’s arm for a brief moment before taking to the skies once again.

We brought some Salmon paste along with us, and 2 minutes after adding our concoction to the many strategically placed banana skins lining the path, a Purple Emperor came flitting down from the trees and floated around our legs – the smell seemed to have worked! Walking back several hours later, we also encountered a male feeding on the bright orange paste, his yellow proboscis tucking in and completely oblivious to us as we busily snapped away with our cameras.

During the day, the males will often fly to the ‘Master Tree’ that provides a vantage point for passing females, and they can often been seen congregating with flashes of purple as the light hits their wings, so we were quite lucky to have them on the deck this late in the day.

Purple Emperors are definitely one of the most striking butterflies in the British Isles. Sometimes appearing black with white bands across the wings, if the angle is just right the wings of the male will explode with a magnificent iridescent purple sheen, which is a result of light being reflected from the structure of the wing scales (brown females don’t have this sheen).

We had the most luck with the Purple Emperors in the adjacent Lady Wood, having parked in the small car park on Harley Way and walking along the gravel path to the next set of trees. I’d had the majority of Purple Emperors here on my last visit, and sure enough, the exact same stretch of path was where we encountered our first this weekend.

Looking up at the pine trees lining the hedge, we could see 4 or 5 at once flitting between the trunks, often landing on the pine needles and chasing each other through the trees. Usually associating with Oak, it was really interesting to see them favour the pines – there may have been an abundance of honeydew or sap luring them in.

As well as ‘his majesty’ (as the Purple Emperor is often referred to) we enjoyed a fine supporting cast of several White Admirals and a cracking Silver-washed Fritillary that favoured one bramble patch in particular at the left hand side of the path. 

The rides were also alive with Ringlets, Meadow Browns and both Large and Small Skippers, but as the afternoon clouded over we couldn’t find the White-letter Hairstreaks that also share the tree top canopies with the Emperors.

A Beautiful Demoiselle flitting gracefully along the path, far from its usual stream haunts, was a damselfly first for me, the jet black wings standing out even from a distance and the gorgeous iridescent marine blue body ensuring the damselfly really did live up to its name. We tend to get mostly Banded Demoiselles around here in Cheshire, so it was great to see this species.

With the spectacle of Purple Emperors at Fermyn woods an annual occurrence, this really is a great woodland to enjoy the delights of these enigmatic butterflies, and I’ll definitely be returning again to photograph and admire this star species.