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Monographs
Some of you may have come across Dennis Dell's intriguing monographs as cited below. If we print any more the academic journals concerned will get stroppy, but I'm very happy to pass on any enquiries to Dennis.
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Distribution of Salix caprea
http://www-saps.plantsci.cam.ac.uk/trees/willowgoat.htm
The distribution map featured on the above site suggests that iris larvae should have no problem deriving sustenance anywhere in the British Isles, with the foodplant being pretty much ubiquitous apart from some parts of western Ireland.
This puzzled Heslop - he spent much time and energy investigating subspecies of caprea, speculating that a tougher, crinkly-leaved ssp. was unpalatable to the larvae, and that the boundary between this western ssp. and the tenderer ssp. coincided with the iris frontier in Wiltshire and Somerset. After experimenting by transplanting Sussex caprea to western Somerset, he concluded that no ssp. was involved, but that the plant responded to rainfall, producing a leaf that was unpalatably coarse in Devon and Cornwall.
Has there been any more research along these lines?
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Resource 3
The Purple Emperor 'Master Tree' Project
Matthew Oates
The Purple Emperor has always been shrouded in mystery. It is this mysterium that makes it, rather than the Swallowtail, Britain’s premier butterfly. Our challenge is to determine its conservation requirements without shattering this precious element, a fate that inevitably befell the Large Blue on reintroduction.
The mystery centres on the concept of the 'Master Tree', an ancient term of unknown origin that holds that Purple Emperors assemble annually around certain trees, with specific branches or even sprays being used annually. Frohawk and Tutt write about Purple Emperors gathering in late morning around a clump of oaks on a little hill at Chattenden, NE Kent, Frohawk adding, ‘some distance from sallows’. It is important to note that both authors were writing after the butterfly had died out from those woods, for contemporary information would not have been publicised. It is hardly surprising that no description or location of a 'Master Tree' appears anywhere in the literature, not even in Heslop’s monograph, Notes and Views of the Purple Emperor.
Heslop’s diaries reveal that he never found any 'Master Tree' that attracted the species consistently for more than two or three years, and never searched for 'Master Trees’ on high ground. In fact, his main 'Master Tree' was in a low point, along the road that separates Blackmoor Copse from Bentley Wood. It functioned intermittently. His searches were limited to roadsides and rides along which he could drive, to facilitate the use of the 37½ foot high net with which he took almost 100 specimens!
Ken Wilmott broke the mould. In the late 70s he discovered, albeit accidentally, two 'Master Tree' locations on high points at Bookham Common, Surrey. These have been used annually for at least 25 years. He must be the first person ever to divulge a 'Master Tree' location, describing them his 1987 WWF report and in his BBCS booklet, and guiding visiting groups to the locations. The account of Purple Emperor male assembly in Jeremy Thomas’ 1991 book is based on Ken’s work and the scanty accounts in the old literature.
In the mid 90s I visited Bookham with Ken and noted that the two 'Master Tree’ locations, or territories as Ken terms them, were in distinct arboreal and topographical situations – sheltered high point woodland glades. Ken is understandably hefted to Bookham in July, and the Bookham model had not been tested elsewhere. I determined to do that. At the same time Liz Goodyear and Andrew Middleton independently decided to do likewise in Hertfordshire, inspired by Ken’s booklet.
As long ago as 1971 I found a 'Master Tree' in West Sussex, a clump of birches around which males soared and battled in certain weather conditions – until it was felled by the 1987 hurricane. In 1975 I discovered Straits Inclosure, Alice Holt Forest, where iris was relatively common. This wood is on flat terrain, with a fairly even canopy height. Sightings of males after lunchtime were so rare that I concluded that they spent the afternoons doing absolutely nothing, high up. Some do, but during these last two years I have realised that many do something radically different.
In 2001 I found a male assembly point on the edge of Alice Holt, by searching for a situation comparable to the main Bookham territory. This is a small spinney in a large garden, just over the crest of the ridge and well sheltered from prevailing winds. It is 250m from an obvious breeding ground. In numerous subsequent visits throughout the flight seasons I have never failed to see at least one male on territory here in reasonable weather. Sightings of clashing and chasing males are common here, and are characteristic of these assembly points. The favoured spot is a beech bough in a small gap adjoining the tallest tree. Males battle amongst themselves each afternoon, fighting for possession of the gap and the beech perch. Late in 2002 I realised that this is one of a series of territories in similar sheltered high point glades along the ridge that effectively runs north to south through Alice Holt. Since then, four major territories, in daily use annually, have been found, plus five others that attract lesser numbers intermittently, depending on weather conditions and the state of the flight season. All are around glades amongst broad-leaved trees in sheltered high point situations, where activity takes place out of the main air turbulence. This amounts to a sophisticated form of hill-topping. It is crucial to note that activity can be restricted to very small areas – commonly <.25 ha. Males migrate to these places daily, except in extremes of heat, cloud and wind, before dropping down slope in early evening. It took me 30 years to discover that some males leave Straits Inclosure in late morning, seemingly heading towards high ground assembly points, whilst others establish territories in a sizeable part of the wood that holds the oldest, tallest trees. Would that I had known that the 1970s, when the population was considerably larger!
The 'Master Tree' Project was formed to conduct similar studies in other woodland systems. Searching for these sheltered high ground territories is proving to be an invaluable survey technique – the butterfly was unconfirmed from Hertfordshire before Liz and Andy employed the technique there. I have also developed monitoring methodology, which works well in many of the major territories. Studies have commenced in the Oxford woods, in the Bentley Wood system, in West Sussex, and in the Northamptonshire woods, which may well hold the best populations nationally. Studies are also getting underway elsewhere within the Purple Empire. Annual reports are produced, which are available on request (contact matthew.oates@nationaltrust.org.uk) and which will lead to a major publication.
The Project aims to locate, stimulate and facilitate searches for male assembly points; liaise with relevant land owners and managers; develop methodology for monitoring adult numbers in assembly points, increase conservation knowledge; publish annual and final reports; above all, make this wonderful butterfly more accessible to people of all walks of life.
Our provisional findings are, firstly, that the concept of a single ‘Master Tree’ may well be a misnomer, but that there are ‘Master Territories’, especially in sheltered high point situations, and that there are also secondary territories. Secondly, that the butterfly may have different assembly strategies in different arboreal and topographical situations. Thirdly, that this is a highly mobile insect that can undertake daily migrations.
It is becoming increasingly apparent that quite a few 'Master Tree' situations have been known for some time, but have either not been recognised as such or have been kept as closely guarded secrets. It would be helpful if more of this type of information could reach us. For those wanting to go out and search for these wonderful places: study the contours on large scale maps, foresters stock maps, and aerial photos; prospect likely spots during the winter, and visit in reasonable weather after 12.30pm during the flight season, Enjoy and report back!
The glory of it is that we have no idea why a significant percentage of males migrate to these highly localised and specific places in the afternoons, where they behave despicably towards each other. It seems unlikely that they do it for courtship and mating, for females appear to avoid these spots like the plaque and males search frenetically for females in the sallow breaks on low ground during the mornings, with some success. I have no desire to determine why, for that would shatter the mysterium of the iris.
(reproduced from 2004 Butterfly Conservation Hampshire & IOW Branch annual butterfly & moth report).
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Resource 4
Personal Observations of Courtship and Mating in Apatura iris
‘We had the experience but missed the meaning’ TS Elliot
Matthew Oates
My diaries indicate that I have observed Purple Emperor adults on 300 days since seeing my first iris in 1970. This figure only includes days of suitable weather during the flight season, whereon the butterfly was seen, and excludes days spent in search of the immature stages and days spent prospecting sites. Most of the 300 days occurred during the periods 1971-1980 inclusive and 2000-2006. Nearly all my observations have been carefully written down, often in some detail.
Despite this effort, I have definitely observed Purple Emperor in cop on only a single occasion, 11th July 1976, in Straits Inclosure, Alice Holt Forest, Hampshire. My diary recalls:
‘1.59: Male A. iris was seen following a female around at 40-55’ … the male following the female and always keeping within a foot of her in a slow, graceful flight around and over the topmost sprays. On two occasions the female almost settled on shaded, topmost sprays of oak but the wind seemed to put her off. Then unfortunately they both floated away eastwards.’
However, all was not lost:
‘2.45: (the same) male and female were spotted together in the south of the glade, rising up from 5’ by the end sallow to 25’, the male following the female and keeping very close to her. She then inspected a few oak sprays in the SW side of the glade before settling 25’ up on the upperside of an oak spray and the male settled a second behind her on the same leaf and alongside her, about an inch apart on a broad oak leaf in half sun – half shade. Half a minute later they were in cop, motionless and with closed wings. Within half an hour they had both turned through 180 degrees. And so they remained … motionless despite a light – moderate (SE) wind for 3½ hours before parting as suddenly as they had joined, at 6.20. They sat together sunning their wings for a couple of minutes before taking off together eastwards, the male circled right round the female before zooming off NW at a surprising pace. … Incidentally, I doubt it was the female’s first mating since she had lost a lot of scales and had tares in her right forewing and left hindwing. … We did see the female the following day but she didn’t seem to be laying.’
This sighting took place on a hot afternoon (25C) rather late in the great 1976 Purple Emperor season (indeed, the flight season all but finished on 14th July). It is highly unlikely that this was the female’s first mating. The pair met along an east-facing edge of tall oaks across a narrow ride from a major breeding ground (a younger oak plantation some 2ha in area that was choked with tall sallows). During all but the end of the 1976 season males were regularly seen patrolling the top of the tall oak edge. I saw a pair courting there at 2.11 on the 10th July 1976, the male following the female closely in the style of the White Admiral. Females were so frequently seen from the narrow ride that year that on the 6th July I had 22 sightings in 2½ hours, including four females in flight at once! Also, on 2nd Aug 1977, at 3.10, a male was seen following a female closely in this same glade. Pairing may have occurred, high on oak, just out of view.
At 1.10 on 24th July 1979, another good iris year, in another part of Straits Inclosure, two males appeared in a close follow-my-leader flight behind a female. The hind male soon departed but the lead male pursued the female, which settled at the back of a tall sallow, fractionally out of view. I am fairly certain that they paired there, as I would have seen them fly out. Shortly afterwards it began to rain.
Until 18th July 2006 I had observed courtship flights on only 20 occasions. This figure excludes observations of females clearly rejecting males, by spiralling down and successfully losing the circling male. This behaviour is fully described by Willmot, 1987 & 1990. There are only 13 records of this rejection mode behaviour in my diaries, suggesting that, like receptive courtship, it too is rarely observed. No less than seven of these rejection sightings occurred during 2006.
My first observations of apparent courtship flights were in 1975, when first (10th July) I saw a male following a female closely over sallows at 11.45 and, second, saw a female spiral down beside a wood edge, followed closely by a male, from 40’ to about 5’, before the pair ascended together and flew off as before, in a ‘dithery, slow and talkative flight.’ It is interesting that this latter sighting, together with the pairing, including females spiralling down in apparent rejection mode. This suggests that spiralling down does not necessarily indicate or implement rejection.
The following table depicts all my records of observed courtship. The three Strategy categories are Sallow-searching (S-S), Master Tree (M T) and Oak-edging (O-E). Sallow-searching means the male probably encountered the female by searching sallow stands; M T indicates that the pair encountered each other in a known male 'Master Tree' territory; O-E indicates that the pair met up along a tall line of oak-dominated trees abutting a breeding ground. It seems likely that these three categories are the main methods of finding mates. The first two are explained in the 2006 'Master Tree' Project Report.
The Oak-edging technique only really became apparent when I researched for this paper, though my diaries clearly show that it was widely practised in one part of Straits Inclosure, Alice Holt, during the late 1970s and, furthermore, it has been extensively observed in Fermyn & Souther Woods, Northants, in 2005 and 2006. It may be a technique practised when populations are strong, during the first half or two-thirds of the season, and perhaps only or mainly in hot weather. I will look for it in one promising part of Alice Holt during 2007.
Date
Time Location Strategy Comments
10:7:75 11.45 Dragons Green, W Sussex S-S M found f in sallows. Close follow-my-leader flight.
15:7:75 6pm Dragons Green, W Sussex M T M intercepted, f spiralled down, but both flew off together.
10:7:76 2.11 Straits Inclosure, Alice Holt, Hants O-E M met f along oak-edge close to breeding ground
11:7:76 2.45 Straits Inclosure, Alice Holt, Hants O-E Pair appeared together. Ended in cop on oak. Observed.
2:8:77 3.10 Straits Inclosure, Alice Holt, Hants O-E Met along oak edge by breeding ground. May have mated, just out of sight.
29:7:78 12.04 Straits Inclosure, Alice Holt, Hants ? M seen following f briefly.
24:7:79 1.10 Straits Inclosure, Alice Holt, Hants S-S 2 males appeared following 1 f. 1 m gave up, 1 stayed. Pairing almost certainly took place at back of tall sallow – just hidden.
4:8:79 12.00 Straits Inclosure, Alice Holt, Hants S-S Old (? Mated) f flushed out of sallows and pursued by 2 males.
Date
Time Location Strategy Comments
26:7:81 11.30 Straits Inclosure, Alice Holt, Hants S-S M found f resting in sallows, closely pursued. Reappeared then both vanished.
14:7:83 3pm Crab Wood, Hants ? M seen following f for 2 mins then both flew away.
16:7:94 11.23 Straits Inclosure, Alice Holt, Hants S-S M flushed f out of sallows, flew around together for 2 mins then flew away.
10:7:99 2.30 Bookham, Surrey M T Courting pair seen over Mark Oak M T for 2 mins.
2:7:00 1.30 Bookham, Surrey M T Courting pair seen briefly over Mark Oak M T.
15:7:00 4.10 Bookham, Surrey M T M following and dancing with a f in main Hill Farm territory, then flew away together.
28:7:01 2.00 4 Winds, Alice Holt, Hants M T M seen following f closely and away.
13:7:02 1.05 4 Winds, Alice Holt, Hants M T M seen following f briefly, soon lost.
9:7:03 12.30 Marlpost Wood, W Sussex S-S M flushed f out of sallow break, then f-m-l flight, and away.
12:7:03 1.45 Bentley Wood, Wilts ? M seen chasing f briefly along ride edge well away from breeding ground and male territory. Odd sighting.
12:7:06 11.45 Straits Inclosure, Alice Holt, Hants S-S M flushed f out of sallows, then follow-my-leader flight.
18:7:06 4.15 – 6.16 Goose Green, Alice Holt, Hants M T 12 sightings of males following >2 females. 1 pair nearly joined at 4.18. All sightings were of pairs that had already met.
19:7:06 2.44-5.41 Goose Green Alice Holt, Hants M T 9 sightings of follow-my-leader flights involving ca 3 females and several males. Pairs nearly joined at 2.44 & 4.25. All sightings were of pairs that had already met.
The table shows that seven observations of courtship, including one highly probable pairing, have involved sallow-searching males, all during the first two-thirds of the flight season and all during the late morning / early afternoon period. These sightings occurred in a diversity of weather conditions. I first became aware of sallow-searching males in 1973, when it was widely practised around a new, sallow-lined clearing in derelict coppice near Dragons Green, mid West Sussex. It has regularly been observed in different parts of Alice Holt Forest since 1976. In good years, such as 2003 and 2006, it is observed almost daily in Alice Holt.
The table shows three observations of courtship (and one mating) following ‘oak-edging’ behaviour. In addition, on 8th July 2006 I twice observed females rejecting males along the favoured east-facing oak edge at Fermyn & Souther Woods, Northants. However, no males were patrolling the favoured oak edges there on 16th July 2006, in hot weather late in the flight season.
Prior to 18th July 2006 I had only observed courtship in known male territories (around 'Master Trees’) on six occasions, all during the afternoon. Then, in hot weather on 18th and 19th July 2006, a large number of courtship flights were observed at the main Alice Holt 'Master Tree', Goose Green Old Car Park. It is likely that at least three females, all old, were involved on both days. Pairing nearly occurred in view on three occasions and may well have occurred out of view. This is described in my account in the 2006 Hampshire and Isle of Wight annual butterfly and moth report. The truth is that every now and then, and perhaps in very hot weather, the Purple Emperor seems to enter a new dimension. Observations of courtship in major male territories occurred during the early, middle and, especially, later stages of the flight season, and in a broad range of weather conditions.
My table also shows three instances of courtship wherein I was unable to determine the method of mate-location. These sightings were very brief.
This informal paper suggests that courtship is seldom observed in this species, and that pairing is even more rarely observed. It may also suggest that three distinct mate-location strategies may be used. Much, though, may depend on population size, flight season weather and the woodland structure. At this stage we cannot rule out the possibility of other, perhaps lesser or more rarely used, mate-location strategies being used on occasion.
References –
Willmot, KJ. 1987. The Ecology & Conservation of the Purple Emperor Butterfly. Report for World Wildlife Fund.
Willmot, KJ. 1990. The Purple Emperor Butterfly. BBCS booklet No 12.
Matthew Oates Dillycot, Culkerton, Tetbury. Gloucestershire. 25:1:2007 Privately Circulated
Post Scriptum
The breakthrough occurred in 2007, when I saw three pairings, one of them from start to finish, and also saw several other courtship flights (resultant from sallow-searching and females entering male territories around 'Master Trees' and / or oak-edging). The following is taken from the 2007 'Master Tree' report (Sex in the Woods) –
No less than 4 pairings were observed during 2007. Prior to this year Matthew Oates and Ken Willmott had only witnessed a single pairing each (respectively, Alice Holt in 1976 and Chiddingfold Forest in 1983).
Three of this year’s pairings took place in known male territories (Hill Farm, Bookham, and two pairings in one superb territory in Fermyn Woods), the other resulted from sallow-searching.
At 2.35 on July 9th Ken watched a fresh female come into the Hill Farm territory at tree height, she was intercepted by the resident male, a 1-2 minute follow-my-leader flight (similar to the White Admiral courtship flight) followed before they joined, wings closed, high on a nearby oak. They were still in cop, wings closed, 1½ hours later when Ken departed due to the onset of heavy rain.
At 11.35 on July 10th Matthew watched a male flush a fresh female out of the top of a line of sallow trees in Fermyn Woods South, a 1 minute long follow-my-leader flight followed before she landed on a pine cone at the top of a ride-edge 30’ tall Corsican pine tree and was instantly joined, where they were successfully filmed by Oliver Bancroft for his film Apatura iris. They remained in cop for 3 hours 40 mins, almost motionless and with closed wings, before separating at 3.15. The male flew off but the female remained there for about another hour. Matthew’s 1976 pairing lasted in cop for 3½ hours.
At 3.30 on July 12th Matthew saw a fresh female fly into a territory in Fermyn North, where she was immediately accosted by 2 males. After 3 minutes of follow-my-leader flight she settled high on a neighbouring oak and was immediately joined by a successful male. They were still joined, wings closed, at 4.50 when Matthew left due to a heavy shower. As with Ken’s pairing, they may have stayed together all night. This pairing generated frenetic activity by at least 4 other males, including much searching of nearby sallows and, importantly, males courting each other (in classic follow-my-leader flights, without any clash and circling behaviour). Matthew witnessed very similar behaviour, including ‘courting males’ on two days in July 06 - perhaps because there were mating pairs nearby, plus associated pheromones wafting in the air? At 4.45, another courting trio was seen: the female nearly joined with one male twice, then changed her mind and dropped almost to the ground in classic rejection mode. She then flew up and seemed to lay eggs in a tall sallow, the witch!
At 3.27 on July 14th another pair in cop was seen in the same territory. A male was seen repeatedly pecking at a high spray of a nearby ride-edge oak, close inspection through binoculars revealed a pair in cop in the spray, wings closed and motionless. The female seemed pristine, the male worn and torn. They were still in cop when Matthew and Doug Goddard left at 5.30, Doug having obtained some photos.
The territory that held the July 12th and 14th pairings is a section of tall east-facing oak edge on the southern side of a gentle summit, and across the ride from an ageing conifer plantation. There are good sallows along the nearby ride and in the plantation. Activity is centred around a tall Turkey oak, which may function as a 'Master Tree' but the males also patrol the east-facing edge, exhibiting ‘oak-edging’ behaviour which occurs along at least two other sections of east-facing oak edge within the Fermyn Woods system.
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Resource EXTRA
Purple Emperor 'Master Tree' Project
Progress Report 2006
Matthew Oates, Dennis Dell, Liz Goodyear, Andrew Middleton, Ken Willmott & Ashley Whitlock.
Project Objectives –
The project was established in 2001 to –
• Develop survey methodology to determine status and distribution more accurately.
• Develop methodology for monitoring adult numbers.
• Improve ecological knowledge to assist conservation.
• Locate, stimulate and facilitate searches for male assembly points.
• Liaise with relevant landowners and managers.
• Publish annual and final reports.
• Help people to experience this magnificent butterfly.
The 2006 Purple Emperor Season –
It is clear that 2006 was a very good Purple Emperor year, with a sizeable emergence. However, it was probably not an all-time classic, like 1983. Getting to grips with the butterfly became difficult as adult activity became heavily suppressed by excessive heat as the flight season wore on. Also, as in other seasons dominated by very hot weather, the main flight season was somewhat shorter than usual, though a few individuals lasted till about the normal modern finish date. At many sites the butterfly was very hard to see after 21st July.
The previous season had been quite a good one, probably with a large egg lay. March 2006 was cold and April dry and cool. Purple Emperor larvae did not commence feeding until the end of April. After a promising first half, May became the wettest since 1979 and one of the wettest ever. Evenings during the second half of the month were mostly unsuitable for feeding Emperor larvae. June was sunny, dry and warm, with a series of anticylones from the Azores. There was only one wet day (the 26th). Purple Emperor larvae were able to pupate quickly and the insect probably spent a relatively short time in the pupal state. It seems likely that Purple Emperor adult numbers benefit greatly from a good June.
July began with an intense anticyclone with temperatures around 30dC. This ended with a thundery breakdown on the 5th-6th, with heavy downpours in most parts of central southern England. The weather was rather indifferent between the 7th and 10th (inclusive), with limited flying opportunities due to cloud and / or wind, but another intense anticyclone developed from the Azores on the 11th. It was virtually cloudless from the 11th to the 21st (inclusive), apart from a weak front on the 13th, with temperatures above 25dC on each day throughout the Purple Empire. On five days the temperature exceeded 30dC, with an all-time record July temperature of 36.5dC at Wisley (Surrey) on the 19th. During this period Purple Emperor activity was heavily suppressed by heat, and the males especially burnt out rapidly. Thunderstorms broke out widely on the 22nd but another anticyclone then developed, though the weather collapsed during the last two days of the month. Overall, July 2006 was the hottest month on record in the UK, beating July 1983 and August 1995.
The first adults were seen on 23rd June, at Bookham Common, Surrey, which habitually claims ‘early’ males. However, at most sites the first males did not appear before the end of June and the bulk of the emergence took place during early July. Evidence suggests that they came out with a bang at the start of July.
TV and Radio
This project has captured significant attention. Purple Emperors were filmed in Alice Holt Forest for BBC1’s Great British Summertime and Nature of Britain. For both programmes, males were filmed from a cherry picker parked at the main 'Master Tree' site, Goose Green Old Car Park (see account in 2006 Hampshire Butterfly Report). Also, a 30 minute Radio 4 programme on the Purple Emperor was recorded at Fermyn Wood, Northants, on 8th July. An excerpt was included on Pick of the Week. All this helps meet one of our project’s main objectives.
Cracked it (perhaps…)!
Males may well have two mate-location strategies : searching for females around sallow stands (‘sallow-searching’) and awaiting arrival of females at 'Master Trees’. The two strategies can easily be mixed where 'Master Trees' are sited close to breeding grounds. There may, though, be an element of local difference; for example, Liz and Andy are not familiar with the sallow-searching strategy in the Herts woods.
Matthew is strongly of the opinion that the sallow-searching is the primary strategy at a great many sites. Obviously, it concentrates on finding freshly emerged (virgin) females. However, many of the females so encountered are mated, and respond by performing the classic rejection flight described in Ken Willmott’s 1980s works: the female spirals down, leaving the ardent male high and dry. There were a large number of sightings of this rejection flight this summer. Matthew’s experiences this year (see below) may suggest that females mainly resort to 'Master Tree' locations when in need of a second mating. Such matings may be required more in hot flight seasons.
Sallow-searching seems to be a feature of the early and mid season period, when females are presumably emerging, and seems to be most often witnessed during the mid to late morning period. It may be synchronised to actual emergence periods, which of course are strongly influenced by weather and are not confined to the mid to late morning. Certainly, it can take place during the afternoon, as indicated by Liz and Andy below. The behaviour of males in this mode is often subtle, with much perching and spells of quiescence, but there can also be spells of frenetic searching over and amongst sallow crowns. Sallow-searching definitely declines greatly during the latter stages of the flight season.
On 18th July this year, Matthew witnessed a series of courtship flights at the main Alice Holt territory (Goose Green Old Car Park) between 4.15 and 6.15. On twelve occasions males were seen following females closely, in a manner similar to the follow-my-leader courtship flight of the White Admiral. Pairing was nearly witnessed. On one occasion six males were strung out behind a female. At least three females appeared to be involved but the bulk of courtship sightings involved a single worn female who was, presumably, seeking a second mating.
The following day similar behaviour was observed at the same location, between 2.30 and 5.45. Seven courtship flights were witnessed. At one point a female being closely followed by three males almost met up with another being followed by two males. Matthew felt that he saw at least three females being courted that afternoon, none of which were fresh-looking. However, no courtship flights were witnessed on the following two afternoons, suggesting that pairing had finished for the year. At this stage, it might appear that 'Master Tree' locations are occupied by seriously frustrated males, and / or the hyper-sexed alpha males.
Monitoring
It was not possible to carry out detailed monitoring at the garden territory in Alice Holt this year (Alice Holt 1) due to changing ownership.
Monitoring Data from Alice Holt 1
2001 2002 2003 2004 2005 2006
Max number of individuals seen at once
4
3
4
3
3
5
However, good data was obtained from Goose Green Old Car Park in Alice Holt –
Monitoring Data from Alice Holt 2, Goose Green Old Car Park -
2003 2004 2005 2006
Max number of individuals seen at once
4
6
4
7
Min number of apparent males on peak afternoon
8
8
7
12
Ken Willmott saw 7 in a vista at the long-established Hill House Farm territory at Bookham Common, making this a ‘7 year’. Ken has a long run of data on the maximum number of males seen in a vista at this territory - very few years have scored higher than seven.
It does look increasingly as though it is possible to monitor Purple Emperor populations by recording the highest number of individuals seen in a vista in a 'Master Tree' situation, though it probably requires a minimum of 10 hours’ recording on at least three days of good flight weather during the peak season period.
Discovering New Territories
Inspired by the guidance produced by Ken, Matthew, Liz and Andy, a large number of people are now prospecting for new Purple Emperor male territories around the country, and significant new discoveries are being made. It is clear that it is quite possible for relatively inexperienced recorders to find 'Master Tree' territories – providing they have been primed by the reports emanating from the group’s work. Over 10 new territories were discovered in 2006, though these need to hold true in 2007 before they can be fully accepted. Significant finds were made by June Wakeford (BC Surrey) on top of the North Downs escarpment at Oxted, Surrey; by Gail & Steve Jeffcoate (BC) at Holmwood Common, Surrey; by Mark Dawson (NT warden) at Middle Hill on Headley Heath, Surrey, and by Neil Hulme on top of the South Downs escarpment near Storrington, West Sussex. Even Matthew joined in the fun, finding a new territory in Alice Holt, abutting the BC reserve at Bentley Station Meadow (which in itself is a good breeding site), and Liz and Andy also found two good new territories. Note also that this was not the easiest of seasons for survey work, as excessive weather reduced male activity during the second half of the flight season.
Report from Hertfordshire & Middlesex 2006 – by Andrew Middleton & Liz Goodyear
Despite the heat, 2006 was very successful, although there were several days when the heat took away all the enthusiasm to search out new woods and survey for potential territories. Unfortunately, Andrew also had to do a lot of the regular survey work on his own.
The season started on the 25th June, when Joan Childs visiting the Paradise Wildlife Park on the south-eastern side of the Broxbourne Woods complex saw a male Purple Emperor enjoying the delights of Capybura ‘poo.’ The season started in earnest on the 29th June when Andrew had two males at the Northaw territory – our key site for first and last dates.
Highlights -
On the 3rd July, we walked the entire length of the Wormley Woods NNR ridge (2km!) with our heads fixed upwards and thanks to a helpful pigeon found the true territory, a minute gap between oaks. Wormley Woods is different as the high ridge runs through the wood rather than along the edge. The territory was on the edge of the high canopy where it meets the younger sallow rich plantations. We had three males clash here, which for Hertfordshire is very rare.
Visiting Ruislip Woods in Middlesex on the 15th July (the first time during the flight period) we walked to the highpoint (a wood edge but with a housing estate now in the way) at St. Vincent’s Hospital and almost immediately saw a male disappear around the back of an oak. We quickly sensed that this was not the true territory so started walking back along the path again with our heads searching all the gaps and to our delight looking across to a gap could see the males on territory.
Ultimate highlight came quite late in the season on a day when the heat had subsided and we felt more inclined to do some walking! An area to the west of the Broxbourne complex was identified by us in 2005 as having potential and although a wood is named on maps much has been cleared for horse paddocks. All that remains is a wide ‘green lane’ lined with some sallows and the occasional cluster of mature oaks. We thought the territory would be in the tall trees by the houses about 1km along the path. We were wrong but saw a female Purple Emperor flying around a sallow here. We started to walk back quite pleased with this result but realised that whereas we thought we had walked up to the houses, the path actually was quite undulating. We stopped at every cluster of oak to look up and then suddenly Liz saw a male fly beside a tall oak and we knew we had cracked another territory!
We also lead a walk at Hatfield Forest, an NT site just over the Hertfordshire border in Essex. Purple Emperor was the target species - none were seen but the aim was to raise awareness of the species and encourage more people in the area to look. A Silver-washed Fritillary made up for the lack of emperors.
All our sites have low population levels, and patience is a huge requirement, observing behaviour other than territorial is only occasional and this year few females were observed apart from those at Broxbourne egg-laying, taking moisture from the ground or feeding at a sap-run. Our key site for non-territorial behaviour is the Broxbourne Wood Nature Reserve, a site popular with photographers. Here the early bird definitely got the photograph this year with groundings being recorded as early 8.30am. However, after only a few days the groundings stopped and by the date of the first field trip on the 8th July most sightings were of females. The majority of our morning observations to date have been of males intent on grounding or loafing. Afternoons have in previous years been times when they have been seen patrolling the sallows but unfortunately as the sallows grow taller this is becoming increasingly harder to observe.
In March 2006, the revised Hertfordshire Biodiversity Action Plan was launched with Purple Emperor having been added with its own Species Action Plan written by us. We can only hope that this will help ensure positive management in Hertfordshire woodlands – there are unfortunately several woods that need some serious work
Doings in Northamptonshire – by Doug Goddard
29th June The first Purple Emperor of the season was reported.
1st July 15 males were seen by one observer before 10 a.m. All were on the ground, except two flying around waist high. One settled inside a camera bag for a short while. This constitutes a spectacular emergence and very early activity in extremely high temperatures. 7 were spotted by another recorder.
4th July 12+ individuals were reported by a member of the Herts Branch.
8th July Between 10 and 12 O'clock, a number of males were seen on the ground, feeding from the track and on dog faeces. One observer reported seeing three together at one time. One settled and fed on a man's walking boot for a short while. 3 or 4 were at territory round the poplar trees, and, it was estimated up to 10 patrolling a line of oak trees further into the wood, as last year, between 12 and 2 O'clock, not actually reaching the territory. A female was seen to lay an egg shortly after, about 8 feet up in a sallow.
12th July A member of the Herts & Middlesex Branch photographed a male feeding on self-heal at 9.55 a.m. It is very rare to see the species on flowers.
15th July Male activity on the ground now seems to have come to an end. In total, eight were seen today, three flying and perching around the very top of the poplars between 1.10 and 1.25 p.m. The others were mainly flying at low level before ascending suddenly to the tops of the trees, in different areas between 10.00 a.m. and 12.45 p.m.
16th July Matthew worked hard to see 12 males, seemingly all worn, and 4 females. None seen before 11.45 and none reported on the ground all day. 6-7 males active from 1.15-2.00 over the Lady Wood poplar edge.
It seems that the season burnt out here shortly afterwards.
Doings in Upper Thames Region – by Dennis Dell
• 36 people visited 30 localities, including 5 which areas distinctly outside woods. Of the 25 woods searched, 6 were in the Chilterns.
• About 130 sightings were made.
• Territories/ male assembly points. The ‘Piddington Vista’ was confirmed, but with not as many sightings as last year. The northern edge of Finemere (identified in 05) is definitely a territory. Again, the most populated territory was the Oakley Wood car park (Bernwood Forest). An ash canopy gap on the northern edge of Rushbeds was occupied again, but apparently not by more than one or two males. The high point at the eastern edge of Greatsea was frequented by several individuals for the third year running. The tall poplars at the southern end of Waterperry [‘Drunkard’s Corner’] were once again not used.
• ‘New’ habitats . [including sites with no recent records] were: Little Hazes Wood Berkshire; Wytham Woods Oxon;, Penn Wood Bucks; Downley [ High Wycombe], Buckland Common Bucks; Sole Common Berks; Moorend Common nr. Frieth Bucks; Braziers End Bucks; Hodgemoor Wood Bucks; Leygrove’s Wood Bucks; Widnell Lane Oxon; Murcott Village, Oxon. Many of these are significant discoveries outside of current / recent known range (e.g. Wytham, where several were seen in different places, and Penn Woods)
• First specimens seen on June 25th, the last in mid-August (the latest reported nationally).
Doings in Dorset
Dorset is in the process of determining whether it is currently Purple or not. A team from BC Dorset led by Roger Smith is searching in earnest, stimulated by a ‘highly probable’ sighting in 2005 and a ‘possible’ sighting and the discovery of some highly promising habitat in 2006. The chances of the butterfly occurring in the east of the county seem quite high.
A
Excerpts from Matthew’s account in the 2006 Hants & IOW Butterfly & Moth Report –
‘After 36 years of annual, and often intense, pilgrimage one might have thought that Oates had experienced every aspect of the Purple Emperor. Wrong! The horrific truth is that until one has spent an afternoon (or four, as Matthew did this year) 22m up in a cherry picker parked aptly within a Purple Emperor master territory, and looked down upon the Emperor’s machinations, one has not experienced the Emperor at all. Indeed, one has scarcely lived as a nature-lover, for on observing clashing and chasing males from the above and horizontal one starts to appreciate fully the insect’s magic.’
‘The bad news here is that we have been grossly under-rating this wondrously magical butterfly. Seen from above, the iridescent colours of the fresh male Purple Emperor, in flight, continuously and miraculously flash through a spectrum ranging from the electric blue of the male Adonis, through various shades of violet, through royal blue, into jet black, and into and out of the rich purple of the Roman emperors. Simultaneously, the small ferruginous-pink ocellus on the hindwing outer edge flickers on and off prominently. All is juxtaposed with the white bands and spots, which deliver after-images. The overall effect is awesome, especially when three or four males are seen in flight together, each flashing different colour combinations by the nanosecond.’
‘The other key lesson learnt from spending time in a cherry picker is that more individual males are present in these 'Master Tree' territories than I had hitherto thought, with several similar-looking males taking turns on favoured boughs, sprays or even leaves during the course on an afternoon.’ Also, I learnt that individual males are more readily identified from above than from below, as wing upper surfaces wear more distinctively than the undersides.
Intentions for 2007
Mark & recapture, using a high net: to find out whether the same males visit individual territories daily, whether males move between territories, determine adult longevity, and to gain an insight into population density. This work must be restricted to sites where one can safely bring a 10m ‘high net’ to the ground without injuring the butterfly. 2007 could be an extremely good Purple Emperor year, set up well by this year.
Contacts –
Matthew Oates Dillycot, Culkerton, Tetbury, Glos GL8 8SS
matthew.oates@nationaltrust.org.uk
Flight season mobile 07771 971488
Dennis Dell 8 Viney Lane, Fairford Leys, Aylesbury, Bucks HP19 7G
Dennis.dell3@btinternet.com
07986 868747
Liz Goodyear 7, Chestnut Avenue, Ware, Herts SG12 7JE
Elizabethgoodyear@talk21.com
01920 487066
Andrew Middleton 46, Bursland Road, Enfield, Middx EN3 7EX
Acmiddleton@blueyonder.co.uk
020 8245 0847
Ken Willmott 3, Yarm Court Road, Leatherhead, Surrey KT22 8NY
Kenwillmott@freeuk.com
01372 375773 Amended version 18:1:2007
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