The possible influence of light and temperature

As Matthew points out in the preceding blog, the conditions have not been conducive to intensive iris activity.
However, in certain Bucks/Oxon woods during the last week, the numbers have been as good as in the heat wave of the previous week. This last seven days or so have been characterised by leaden skies interspersed with short spells of sunshine, some rain, and temperatures between 17 and 20.
Today, in the best Bucks wood, was instructive: the local forecast indicated temperatures slowly rising from about 16 to 17 at 10 am to 20 in mid-afternoon; the light on the other hand was best in the morning, deteriorating according to Mick Campbell's light meter, from 14.00 pm, which is when I arrived!
From midday until 13.45, Mick saw 24 individuals, mainly high up. He also watched a female ovipositing and we found the egg later. Together, from 14.00 until 16.50, we saw only 15 individuals.
So, from 12.00 until 13.45, temperature 18 degrees, 24 were seen = one every 4.4 mins; from 14..00 until 16.50, temperature 20 degrees, poorer light, 15 were seen = one every 11 minutes. This is not a scientific study, but you could possibly conclude that light is more important for activity than temperature, in the temperature range experienced today.
As Matthew also notes, it was fascinating to stare at the tops of the trees for long periods of time in dull conditions without seeing any movement, and then, suddenly, as the sun shone through for just a couple of minutes, four males took to the air, clashing, separating and gliding before disappearing again as soon as the sun disappeared.
Nevertheless, for this past week in several woods, it was reassuring to note that one could venture out in dull and even breezy conditions and yet see a reasonable amount of activity at temperatures > 17 degrees.

Pause for Breath

There has been virtually no Irisian activity since Monday evening due to a stagnant area of low pressure sitting overhead. The Emperors will not have been decimated, as they can sit out this sort of weather with some ease (summer gales really knock them out, not yesterday and today's cool calm cloud or the slow steady rain of Tuesday afternoon).

At Knepp yesterday and today, they were appearing with every glimmer of brightness, but vanishing whenever the sky glowered. The are desperate to become active, and will erupt when the sun next shines - on Saturday.

Saturday should be terrific. The butterfly will be at peak season. Don't miss out - skip the family wedding, sell the kids into slavery, cancel the mortgage interview, and be there...

A Lesser Being

Iris is here too, but the lesser purple, Apatura ilia, is rather more common at the moment. Also having an excellent season is the False Comma, Nymphalis vau-album, which we've seen at four different localities in the past few days. False Comma is a terrible name, we've renamed it the Splendid Tortoiseshell.

Gornji Krivodol, Serbia

the dangers when you photograph iris

These two pictures were taken by Nick Board, 'our man in north Bucks'.
They are of the same two specimens, photos taken one minute apart. One would be forgiven for concluding, if you received only the photo where they are very close together, that we are dealing with females. The other photo shows quite clearly that they are males!

Wolfing it Down

Apatura ilia not averse to sharing a tasty bit of wolf poo first thing this morning. Topli Do, Serbia

Have you found Richard's keys?

My name is Richard Tyler and I was in Fermyn Wood today looking at those beautiful emperors.

During the day I managed to lose my car key (hole in trouser pocket). Non descript keyring with 

VW Tiguan car key and house key attached. 

Should by any remote chance some body has found them and contacted your blog

I would be extremely grateful to know.

Thank you.

Kind regards

Richard Tyler

(Please contact Richard if you can help. His email is richardtyler@live.co.ku, but swap the last two letters. )

Purple Paradise

On Monday I joined Matthew and Exeter University student Harry Drew, to monitor Purple Emperor and other butterfly numbers over the Knepp Castle Estate Wildland. This was another very thorough and widespread survey, extending over much of the Southern Block, starting at 9.00 am and continuing until the emperors finally stopped flying at 7.40 pm.

Using the 4x4 'mule' we were able to penetrate deep into the seldom-visited parts of the wilderness, to experience a grand finale of 'big sky' and spectacular sunset, as an already-mated empress spiralled to the ground, in an attempt to shake off her suitor. At times being at Knepp can really feel like being in Africa.

The hard-won tally for Harry and I reached 138 Purple Emperor, with Matthew seeing a very similar number, having taken a slightly different route at times. The species has reached peak but the numbers are so vast that the season will run for some weeks yet. Only 8 of those seen were females, several being on sap-runs. Activity was supressed by heat for much of the day, but things became really lively after 6.00 pm. During our travels we also saw 3 Silver-washed Fritillary, 2 White Admiral, 2 White-letter Hairstreak and my first Gatekeeper of the year.

There has also been a huge emergence of Purple Hairstreak, which is best seen in the early and mid evening. We found 6 freshly emerged male hairstreaks on the ground during the morning, which seemed to be searching for moisture amongst the Fleabane and grasses. The numbers seen after 6.30 pm were simply phenomenal, with bundles of up to 15, and 20 - 30 seen simultaneously on some trees. Matthew commented that this was the best showing he has experienced since the long, hot summer of 1976. This is the year to look for this species.

One wonders just how good the Knepp Wildland can get. There is simply nowhere else quite like it.

Bentley Wood

With my holiday imminent and the weather set to crash over the next few days I set off for a quick look at Bentley . Arrived in full sunshine and 21degrees and headed out down the switchback path . Within 50 metres I saw a large dark butterfly circling the ground , it being an immaculate male . Unfortunately as I was about to get a pic a dog frightened it off . This was the best chance of the morning but another 3 separate males were seen in the canopies. According to the log book HIM was first seen on the 19th so probably not yet at its peak , even though an entry was made yesterday of 10 sightings . Compared to last year numbers already seem up .

Ditton Park Wood, Cambridgeshire

Despite the breeze and the cloud cover the warmth building up during the morning prompted a trip to Ditton Park Wood, just south of Newmarket, a 20 minute drive from home.  Two year old Eve only needed a short shoulder ride to a suitable picnic spot dictated by the immediate presence of Himself engaged in sallow searching antics.  2 males and Herself became evident gliding, arcing around and in and out of the sheltered, open canopy of the sallow.  The focal point of activity though centred around a low Hazel, which was vigorously defended.  After several long sorties the male I was following alighted on a Hazel leaf which already had two Emperors, previously unseen, resting upon it.  The three didn't spend long together but I did get a couple of photos which, with a lot of cropping, reveal a female who spreads her wings and imposes herself over one of the males. 

 

Shortly, an aerial scuffle ensued and two spiralled up and tumbled down, entwined with invisible gossamer and into the bracken, heaving with Ringlets today.  Herself took to the wing almost immediately and was off but the male sat long enough for a closer approach, forewing tightly tucked down, eyeless, before returning to the air again

 

 



Activity was continuous for a further 5 minutes with low swoops around a bramble tangle instigated by some plucky Comma's willing to harry the passing Emperors on their loop, in turn perking their interest to return.  Then one male took to the vigil, the other looped us at eye level before banking sharply up and into the Oak canopy above and behind us.  There were several Purple Hairstreaks flying between trees and on the Hazel allowing reasonable views through binoculars.

 

 

 

A little wander further up the path revealed a couple more canopy areas occupied by Emperors and I think there were at least 6 individuals.  A great hour out, I'm so happy to have an accessible and productive purple wood near to home, a true luxury.







Curiously Finemere Wood in Bucks was deserted of people this afternoon but fortunately there was plenty of Emperor action on offer. This fine fella landed on my jeans as soon as I entered the wood. I transferred him to my finger where he stayed licking salts from my hand for the next 50 minutes. I did a tour of the main ride up to the turning circle and back with him in my company.

The light was perfect to get a good look at him excreting fluids onto my finger and sucking them back up presumably extracting the salts from my fingers.

There were several other males actively searching the Sallows along the main ride looking for females. I think Dennis is correct, we are close to peak in the Bucks woods.

Lies, damn lies, and statistics

This is especially true for biological data, because of the huge variation. I do this just to provoke Matthew, because he hates trying to tie down that independant spirit, HIM, with numbers. Nevertheless, I do have a lot of data, gleened from the observations from about 30 Upper Thames enthusiasts each year since 2003..
Only from 2009, however, are the data sets large enough to be able to do anything useful with them. For instance, I have been asked the question, what is the time between the first sightings and the beginning of the peak flight period?
So, for this 8 years, 2009 to 2016, the average time was 10.5 days, with a 90% confidence interval of 8.3 to 12.7 days. For example, for this year, the first sightings at Knepp were on the 14th of June, or thereabouts, suggesting that the peak starts from 22nd until 27th June. In the Upper Thames region, the first sightings were on the 17th June, giving the start of the peak from 25th June until 30th June.
We have seen that the peak is rather extended, lasting between one and two weeks.
Depending upon how reliable this is, it is unlikely that we will be seeing many Emperors after mid-July, although we will see tired Empresses.
I look forward to being struck down in ignominy!
All the raw data is available from the appendices of our annual reports, which are accessible on the Upper Thames website, under 'species champions' and then 'purple emperor'.

Wedding & Bedding in Fermyn!

Phenomenal day in Fermyn Woods with Neil Hulme & Andy Wyldes, but hardly anyone else. This is the peak weekend of the 2017 Fermyn Emperor season and the woods were almost devoid of butterfly people. Perhaps some people don't realize that the Emperor is out, or maybe they haven't been able to bring their booked July pilgrimage forward? I fear there will be a lot of disappointed visitors there in mid-July, which is galling as the butterfly is out in very good numbers this year.

Despite a lot of cloud, which rendered it too dull for Emperor activity at times, the butterfly put on a memorable show. I saw two pairings, high up in oak tops, and two other courtship flights. Here's one pair, the other was tucked well into the spray and impossible to photograph - 

As usual, a third male tried to muscle in -

Curiously, the males were scarcely coming down to the ride surfaces today, whereas yesterday they were dropping down at every opportunity. Instead, today they were frenetically searching the low tree tops. I suspect this was because there was a big hatch of females today, and that we were witnessing the Fermyn festival of wedding and bedding.

We were greeted by a male down at the main entrance, crawling under a car. Here's Neil dealing with this recalcitrant butterfly -

Of course, the police were called and weren't impressed by his explanation. Mr Hulme is still helping them with their inquiries down in Corby nick.

I'm off to Knepp tomorrow... ... ...

Doings in Fermyn...

Neil and I were in Fermyn Woods today, working with BBC Countryfile and living legend presenter John Craven to film The Emperor's Breakfast, for transmission on Sunday July 9th.

Despite a lot of cloud and marginal conditions the Emperor was on good form, and was highly obliging. Several males came down to our baits, both on the breakfast table and on shrimp paste puddles on the nearby rides - and it wasn't just shrimp paste and fermented sardines, for a particularly smelly runny French cheese (worse than Stinking Bishop) was favoured.  

On several occasions we saw vistas of three males, patrolling the oak tops. I also witnessed a classic 'tumble-down' - mated female rejecting an amorous male.  

It looks as though this will be the peak weekend for numbers and activity at Fermyn, where the butterfly commenced on Sat June 17th.

The other day a pristine female ab. lugenda was photographed in Fermyn, by Lucy Milner (the poet Edward Thomas's great-granddaughter). She's sending me the picture, which I'll post here.  

Here are some memories from today -

When it comes to eccentricity Britain still has what it takes... ... ...

Is it peaking in June?

In the top Bucks wood yesterday afternoon, there was no sun, a very brisk breeze and a temperature of 20 degrees. Just 12 were seen in 66 minutes, all high up, clashing and gliding around the Oaks and Ashes. Little Sallow searching. When I retraced my steps along the ride where I had seen 6, about 30 minutes later, none were to be seen. I have seen this before: presumably, they are not constantly on the move and have periods of respite in the trees.
Today, the Campbells spent 140 minutes in the wood, in similar weather conditions as yesterday, and saw 43, so they have not peaked yet.
It is good to know that in woods where the numbers are high, we can go looking even if there is no sun; as long as the temperature is in the late teens, we will see activity.
A few days ago we were in Little Wood Oxon which is on a very steep slope. A very large wide Ash at the top of this slope is normally a banker for seeing activity; we saw nothing in 15 minutes. We went down the slope to the bottom where the trees are very close together, allowing poor views of the tree tops. In one small opening, however, we were treated to two pairs of males clashing.
Nothing is certain or predictable in the Emperor's world!

Abbots Wood

Lucky again with the groundings. It seems to me that there are more individuals around this year with plenty of activity mid to late morning along the main ride. Even spotted one settling onto a pine tree at the top car park.

Midsummer Madness As British Emperoring Record Tumbles

Exeter University student Harry Drew had never seen a Purple Emperor before arriving at Knepp, for what must inevitably become an unforgettable summer as a resident research volunteer.

I met Harry rather late in the morning, for an introduction to Knepp and its emperors, but wasn't expecting the fireworks we were about to experience. This was about to become a Midsummer Day I will never forget, and nor will he. I had already commented that this year's population size was hard to call, as the searing heat over previous days had clearly suppressed activity - but by how much?

Heat again subdued activity, but this time only between 3pm and 6pm, with the slight breeze preventing burn-out before this period of quiescence. Our meticulous and methodical count, between 10.30am and 8.00pm, of 148 individual Purple Emperors could thus have produced even more.

Of the 148, only 6 were female, and almost every butterfly appeared to be in excellent or good condition. We saw 6 or 7 different bundles of 4 males, and between 15 and 20 bundles of 3. Some oaks hosted clusters of 4 and 3 simultaneously - the air was at times thick with them.

The Knepp emperors are now coming to ground with increased regularity. We witnessed 3 groundings and I'm aware of another 3 on the day. We watched one 'rejection drop', with the disgruntled female being pursued by a couple of males. Chaffinch, Great Tit, Chiffchaff, Jay and large dragonflies were attacked.

As the light of the longest day began to soften, and the oak crowns became alive with twisting clouds of Purple Hairstreak, the emperors finally decided that they'd done enough to confirm that Knepp is now one of the most awe-inspiring parts of the great British countryside.

Kneppic!

Yesterday my friend Nick and I spent a long day at Knepp and had our best-ever day of emperoring.

I’m pretty sure Neil Hulme will have more enlightening updates shortly as I know he was racking up some serious numbers at the site, but Nick and I saw approximately 90 emperors including some memorable encounters and a superb, hotly-contested territory.

First off, at about 9.45am I saw a grounded male on the path near(ish) to the hammer pond. It later transpired it was on or near to a spot that Neil had baited – Neil asked me to post the photo to the blog. Here it is. The emperor was flighty. 

Later in the day (2 pm-ish) we were watching beautiful demoiselles in the ditch in Green Lane when we suddenly realised we were looking at an empress sitting so still in the mud that we hadn’t initially noticed her. She appeared to be drinking at the edge of the water in the ditch, and soon flew off.

Thanks to a conversation with the site-owner, Charlie, during a break in the Go-Down, we then searched what is a new stretch for us – the circuit adjacent to the hammer pond - in which we found a ride that was a stunning hotspot with a territory consisting of two or three oaks next to a prominent dead oak.

In this little stretch we experienced emperor madness: within minutes we saw a battling sextet of emperors with another pair in the same air space flitting around 20 metres or so away from the main cluster – by far the biggest emperor scrap I’ve seen. Not very surprisingly we walked up and down this ride for a while and saw many groups of four, three and two males fighting. I’ve never seen such a concentration of emperors in one 200-yard transect. 

The high level of activity continued almost unabated and it was notable that in this stretch the emperors were “flirting” with the ground and often landing obligingly low in the sallows along the path. (We saw similar behaviour in Green Lane in the pm, though with lower numbers).

We decided to retire briefly again to the Go-Down to recharge before a final evening stint, and in the evening light, a few hundred metres past the first tree house, we almost stepped on a male emperor feeding on a fox scat. He was pretty settled and returned for a second grounding in a different spot. 

There were plenty of emperors around this ride at that point, with quite a few coming low and one landing further away on the path but not allowing us to come near. They were notably more obliging than earlier in the day and I’m guessing evenings are good at Knepp during these blisteringly hot days – meaning a quick evening stint could be really rewarding for anyone local enough to make it. 

We also saw white letter hairstreak (thanks to Neil), purple hairstreak and white admiral.

It was an amazing day at Knepp, and was notable for more groundings than I’ve seen there before. 

Alice Holt

Emperors have been scarce at Alice Holt with just the odd one or two showing during the day - probably due to the heat I guess - so I paid and evening visit which paid off. I had three grounded males between 6:15 and 7:15 and half a dozen were oak edging looking for females.
Kind Regards
Mark

Too hot for HIM? At Fermyn

A reasonable day at Fermyn and Lady wood. Plenty of sightings but only a dozen or so groundings despite the odd baiting along the rides. One male rudely refused the proximity of my bait only to settle and imbibe aphid dew on the leaves of a nearby bush. I was pleased to see one female gliding low along the track margin giving me a frustrating pursuit for a distance before finally settling long enough for a photo. Perhaps with temperatures predicted to drop, Fermyn will kick off properly in the next few days.

Knepp showing strongly

Myself and my girlfriend made the long journey from Dorset to Knepp today to get our fill of purple . On arriving the heat was intense with just meadow browns and marbled whites showing . Fearing it was too hot we got to one of the main "hot spot " rides which was on the shadier side and instantly the Emperors showed themselves . Most of them making brief flights over the sallows then back to the oaks for shade . Occasionally a few battles took place but it was only half hearted . Highlight was a female getting intercepted by a male and after a brief chase they settled high up presumably to pair up . The difference in size between them in flight was striking . In total we had 21 sightings with a supporting cast of a White Admiral and a few Purple Hairstreaks . My holidays will now interrupt the Emperor season but hopefully they have not burnt themselves out in a fortnight for a return visit . Sadly no photos as no groundings and those we could see were out of camera range .

Violence!

Impressive photos of serial violence, by Tony Rogers, at Knepp Wildland - 

Upper Thames first sightings

Several were seen in the known territories of Waterperry Wood and Little Wood Oxon on the 17th, which is several days earlier than usual.

Shortly before 4pm today at Piddington Wood, Oxfordshire a paired couple of iris came spinning out of the canopy quickly pursued by a Sparrow. They landed on the path just in front of me with the Sparrow still trying to grab an easy meal. I shooed the sparrow away as quickly as I could and the iris pair appeared unharmed. They were rather exposed and in danger where they were so I carefully picked her up with him in tow and placed them in the under growth. She immediately started licking salts off my finger so appeared undisturbed by the experience. Fortunately they were still together when I left them to it.

Noticeably her wings still appeared to be quite soft so I assume she had only emerged today.

Chiddingfold Forest produced many Emperor sightings this morning.
It is thought that the multiple groundings, we saw, were of two males
making return visits to their favourite delicacy.
There were flybys on several occasions, whilst the two on the ground
indulged.
Yesterday the weather was probably too hot for any groundings,
but today the air felt a little fresher, on the walk from the car, filling
me with optimism, and this was rewarded with some great sightings.

Trevor.

Good Morning at Abbots Wood

Having drawn a blank on Sunday I decided to have another go this morning. A lot of activity along the lower part of the main rides late AM with 2 groundings. They didn't settle long enough for decent pictures but were in pristine condition. Myself and another gentleman managed to get close to one perched on a beech sprig, picture to follow later. Nothing at Goose Green on Sunday and I have to wonder if the fairly drastic clearance of the hedgerow bordering the road will have an impact.

Hot Stuff At Knepp

It is still too early to judge how well Knepp will perform this season, not least because it's too damned hot. The intense heat is really supressing activity (and the counts) and areas known to be well-populated can appear to be bereft of emperors for long periods, only to burst into life when a wisp of cloud takes the sting out of the sun, or as the evening cools.


Yesterday (18 June) I made a count of 32, including a respectable 20 on the green lane transect. One came down briefly to a fox scat. A remarkably early egg-laying female was also seen at close range.


I was absent this morning, but Andy Wilson photographed a pristine male on the deck, and saw several more perching low in the sallows. By the time I arrived, mid afternoon, things were very quiet. It was after 6pm before I finished the green lane transect, having seen just 11, plus 6 elsewhere. However, things started to liven up and as I searched different areas the total rose to an encouraging 36. They were still active at 7.30pm and attacking Purple Hairstreaks with typical enthusiasm. Just a single empress seen today.


Purple Hairstreak numbers have been low until today, but by 7pm they were forming bundles of up to half-a-dozen. In all, about 40 seen.


As the sun threw its magical evening light low across the oaks, and with the place to myself, I experienced Knepp at its best, to the soundtrack of Cuckoo, Turtle Dove and distant Longhorns. But it took a lot of patience today. Can we have a little light cloud please?

Coming Out Strongly

Browsing through the BC branch websites, and via Twitter, it's clear that iris is coming out well at most southern sites now. Several counties kicked off yesterday and today (e.g. Oxon, Middx), or over the weekend (e.g. Hants).  Many counties have clocked their earliest ever record, or at least since 1893.  

He wasn't out in Savernake today, and I don't think Fermyn's kicked off yet.

It's too early to judge numbers, but they seem to be up on last year. Activity is being suppressed by heat - advise: don't look for them in the heat of the afternoon, try again in the early evening (5.30-7.30)

'To the woods, without breakfast!' (Heslop, diary).

(I'm having a rotten time counting High Brown Fritillary on Exmoor - iris and adippe used to occur in the same woods together, and roost in the same oaks...).  Back Emperoring on Friday.  

Knepp looking good

Visited Knepp yesterday (Sunday 18th June) with my better half Kate. We patrolled the site from about midday until 4.30pm in sweltering conditions. We wilted.

Even in these early days, we saw at least 32 emperors, including a trio of battling males and a couple of fighting twosomes. Caveat: I’m not knowledgeable enough to know whether we saw the same individuals repeatedly! (The info board in the Go-Down showed that we weren’t the first people to make a count of 32 yesterday...) 

We witnessed the usual thuggish behaviour, watching an aggressive male stake his claim to a lofty oak perch and chase off anything that came by, including an outclassed red admiral that got a shoeing when it strayed too close. 

We also met an inquisitive deer fawn that approached us to within two metres, our first white admiral of the year - and Neil Hulme, who kindly pointed out a purple hairstreak or two for us!

We were so exhausted from the heat when we got home that I told myself I won’t need to return to Knepp for a couple of weeks. One sleep later and I’m already wishing I was back there. 

Good hunting all. 

My earliest grounding.

I visited Straits Enclosure at Alice Holt, Hants today without success, one chap I had spoken to had already given up, thinking it was too early. I decided to give nearby Abbotts Wood a go. With cyclists zooming up the track I didn't hold out much hope. After searching along the track I decided to walk back to the car. Then suddenly I put a large butterfly up. Looked like a White Admiral, but then the shimmer of Purple. Wow yes, it was my earliest ever grounded Purple Emperor.
It was behaving in a rather strange manner, possibly due to just emerging. It kept drifting into the vegetation and landing on either side of the path before eventually landing to imbibe on the track for no more than 30 seconds or less. It stayed low flying and landing along the track. As it was very hot, it did not stay in one place for long. Eventually it doubled back towards where I first found it and effortlessly drifted up and away. This was the only iris I saw all day, but I did see it rather well so I am pleased my visit proved fruitful.