The 1976
Purple Emperor season was one of the greatest of the 20th century, building
on good seasons in 1974 and, especially, 1975. However, it was an unusually
short season, with numbers nosediving after three heady heatwave weeks – as was
the case in 2025.
Indeed, the
similarities in adult behaviour between the 1976 and 2025 flight seasons are
immense.
Nationally,
the first male of ’76 was seen at Bookham Common, Surrey, by leading
Emperorphile KJ Willmott on June 24th. That equaled the record
earliest appearance listed by IRP Heslop, though Heslop’s diligent searches
through the entomological literature had somehow missed the incredible summer
of 1893, when the butterfly was ‘well out’ in the New Forest ‘by early June’
and a male was taken by a Marlborough College boy on June 10th.
The ’76 season,
like that of 2025, was dominated by heatwave conditions. Indeed, 1976 brought
what was then the UK’s warmest June on record. From June 24th till
July 8th (inclusive), heatwave conditions prevailed: the temperature
reached or exceeded 32C somewhere in southern England for 15 consecutive days. Tarmacked
roads melted – I know, I was on a bicycle.
For the
record, there was extensive rain in the Purple Empire on June 19th-20th;
thereafter rain fell in much of the Empire on July 9th, 13th,
16th and 20th, some of it thundery. Thereafter, there was
virtually no rain until the weather broke at the end of August – and many
sallows wilted, along with veteran beeches. The drought had, though, started
way back in the spring of 1975. Then, after a hot dry summer, the autumn and
winter rains failed – in stark contrast to the autumn and winter of 2024-25
(and indeed 25-26).
All this
meant that there was little if any moisture for midsummer butterflies fifty
years ago. In early July ‘76 Emperors, of both sexes, descended to the parched
rides in early morning (8.30-9.30) to probe for moisture amongst the grasses,
accompanied by numerous Purple Hairstreaks. This phase, though, lasted barely a
week.
In those
days there was little if any dog poo on the rides, as most Emperor woods
discouraged public access – you had to hold an Access Permit to enter many
Forestry Commission woods.
Instead,
there was a super-abundance of ‘honeydew’, the sticky secretion of aphids. During
the midsummer heatwave, the oaks literally dripped with it: Emperors, Purple
Hairstreaks and, curiously, Meadow Browns feasted on it high up. Also, Emperors,
as in 2025, sought oak sap ardently – and even human sweat: I had a male feed
on me on June 29th, and later watched a pair feeding together on
creosote!
In Alice
Holt Forest, E Hants, where I was centred, the first White Admiral and
Silver-washed Fritillary appeared only on June 21st, and the first
Emperor on the 25th. I noted the first definite Empress on July 1st.
By July 6th, they were busily egg-laying – selecting heavily shaded
isolated sprays beneath the main sallow canopy.
On July 10th,
I watched a female ab. lugenda (‘semi-iole’ in the language of the day), at
9.40 and again at 1.30. She was seen once more, in the same sallow glade, on
July 14th.
On July 11th
I watched a courtship flight, which quickly became a treetop mating that lasted
for 3 hours 35 minutes (and must have been the female’s second mating, for she
was distinctly worn).
Suddenly,
around July 12th numbers plummeted, and they were gone. I saw my
last on July 18th, and thereafter concentrated on finding eggs
(which hatched fast in the heat) and larvae.
That summer
saw a resurgence of old-fashioned butterfly collecting – grown men in shorts,
running around with nets. Iris, as it then then called was the main
target species. Nets clashed at the few well-known localities, notably Lodge
Inclosure of Alice Holt Forest, Kingspark Wood (then FC) in Chiddingfold
Forest, and Hell Coppice & Shabbington Wood in Bernwood Forest, Bucks/Oxon.
That summer also saw the birth of butterfly photography.
On several
occasions I encountered the legendary Baron Charles de Worms, Heslop’s closest
ally. At one stage he was dressed in a string vest, Boy Scout shorts straight
out of the Baden Powell era, and corps boots – he was rubbing rancid Danish
Blue cheese into a gatepost, as a bait for iris. We shared an
entomological friend, a retired GP, Dr John Holmes. de Worms was a delightful
man, but it was impossible to get any locality information out of him, and he
shed little light on Heslop, my boyhood hero.
The good
news is that those of us who lived through the 2025 Purple Emperor season have
a pretty good idea of what the 1976 season was like.
What
matters now, of course, is what the 2026 Emperor season will be like. Watch
this space, for one of these years iris will be on the wing in May…
