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2005 BUTTERFLY REPORT ROB PARKER 2005 was the hottest year the Northern Hemisphere has ever experienced, according to climatologists. However, the Suffolk weather was not hot compared to 2003, and was sufficiently erratic to spoil the butterfly season for some species, with heavy rain at unwanted moments. It was an ordinary year for our commonest residents, a depleted year for the Vanessids and an unusually poor year for migrants. The progressive decline of Grayling and Wall Brown continued, and most observers commented on a boring, poor, unexciting or disappointing season. Fortunes were mixed for our scarcer species, with encouraging records from fresh sites for White Admiral and White-letter Hairstreak, ups and downs for Dingy Skipper and a big down for the Silver-studded Blue at Purdis Heath. A couple of rare aberrations were found in the wild, and further excitement resulted from the discovery that Purple Emperor was flying in Suffolk (following releases made in earlier years). Meanwhile, counts from transects showed that numbers were not down by as much as casual observation led one to think. Overall then, 2005 has been notable only for a handful of unusual sightings; generally it has been a year of low butterfly numbers. Weather Average temperatures were again about a degree up on historic averages, but sunshine was only average. Rainfall was low initially, but it was wetter than average in the summer. The table below shows mean temperature, sunshine for and rainfall for East Anglia, all presented as anomalies compared to averages over the period 1961 to 1990. Spring warmth opened the season nicely, but some very wet days inhibited recording activity in summer. Autumn was warm and extremely sunny; sadly there were very few butterflies on the buddleia, but there were plenty of Red Admirals well into November. Table 1. 2005 Weather for East Anglia

Season Winter 04/05 Spring Summer Autumn

Mean Temp Deg C 5Â6 9Â4 16Â5 12

Anomaly Sunshine Anomaly % up hrs % 1Â2 1Â2 0Â9 1Â5

193Â9 435Â0 552Â4 386Â8

115 98 97 121

Rainfall mm

Anomaly %

98Â9 109Â4 152Â4 170Â9

69 79 98 105

Source: Anomalies are measured against the 1961 to 1990 averages

Trans. Suffolk Nat. Soc. 42 (2006)


Suffolk Natural History, Vol. 42

Monitoring the BAP Species This year’s Dingy Skipper survey got off to an excellent start, with a record count at the Wordwell/King’s Archery colony, but a worrying count of just one at RAF Barnham, where grazing by sheep has just been introduced. The Silver-studded Blue survey was blighted by a false start and heavy rain, resulting in incomplete counts at the Minsmere sites. Results elsewhere were mixed, with two newly colonized sites apparently in good health, but a very worrying deterioration at Purdis Heath, where no one saw more than 6. The White-letter Hairstreak was again rather well recorded in 2005, with 9 sightings from previously unknown sites. Over the period since 1995, records have now been made from 84 tetrads, although not all of these represent established colonies, and the steady increase is a measure of recording effort rather than a genuine spread of the species. Separate detailed accounts for each of the BAP species follow as annexes. Migrants It was a poor year for migrants, with Painted Ladies appearing in very low numbers. There were only 16 Clouded Yellow sightings, just one Camberwell Beauty (a late record), and no Queen of Spain Fritillaries. Swallowtails Two adult Swallowtails were seen, one at Trimley and the other on the outskirts of Ipswich. There was no recurrence of the flurry of sightings made in 2004, and no reports of larvae. Residents Orange-tips, Holly Blues and Green Hairstreaks all did well in spring, although Holly Blues were not so numerous in the second brood. By summer, the shortage of Small Tortoiseshells, Peacocks and Commas was a topic of general awareness, and it is possible that they are suffering from the spread of the parasitic Tachinid fly Sturmia bella. Again, there was a very poor showing of the Wall, although the Grayling and Small Heath did not deteriorate below their low 2004 numbers. The White Admiral had a strong year, with sightings in 31 tetrads, including 6 in totally new sites, following a year that produced a partial second brood. The Small Tortoiseshell, noted in 66% of tetrads visited, remains our most widely reported butterfly, though it was closely challenged by the Speckled Wood and the Whites. Purple Emperor The surprising discovery of Purple Emperors flying in Theberton Woods was found to be the result of clandestine releases dating from 2000. It remains to be seen whether they can establish a sustainable breeding population in the wild. Early/Late Records Spring brought only one earlier than ever record – a Brown Argus on 28 April. Autumn was mild, sunny and extended, with the Browns flying later than usual – on 6th October, both Meadow Brown and Gatekeeper were still on the wing. This is later than previous records by just a day for Meadow Brown, but

Trans. Suffolk Nat. Soc. 42 (2006)



by 10 days for Gatekeeper. Speckled Woods, Large Whites, Commas and Peacocks were all to be seen in sunny spells, but it was Red Admirals that were most noticed, with 38 records in November/December. Geographic Coverage Records were received from 500 tetrads, which is better than 2002 and 2003, but does not match last year’s high of 530. In all, over 300 recorders contributed, and “regulars” were joined by new faces, some from SNS, others through BC’s Spring Survey, and a good number through participation in the BTO’s Garden Bird Watch, which encouraged butterflies to be noted alongside birds. Our distribution maps are improving as an increased number of observers record butterfly numbers, rather than simply presence. Species Maps Distribution Maps for individual species have been prepared for our 31 regulars, and these are available for reference as required. This year’s total species count stands at 34 if the introduced Purple Emperor is included. Analysis Relative scarcity can be deduced from a count of the number of tetrads from which each species has been recorded. Our rarest native butterflies are usually the 3 BAP species, followed by the White Admiral. This year’s league table reflects a number of changes, with Clouded Yellow appearing high up as a result of the poor migration season. Encouragingly, White Admiral and Holly Blue are much improved, but worryingly, the Wall was only found in 7% of the squares surveyed. Year-on-year change is not simple to quantify: a straight tetrad count is less meaningful than the percentage of survey squares in which each species was found. Neither measure assesses a butterfly’s abundance at its breeding site as accurately as the “index” derived from transect walks. Transects Detailed data was submitted for the established transects at North Warren (Rob Macklin), Fynn Valley (Richard Stewart), RSPB Minsmere (Robin Harvey), Bradfield Woods (Steve Hunt), Center Parcs (Graham HerseyGreen), Cavenham Heath (Michael Taylor), Walberswick (Adam Burrows) and Bury St Edmunds (Rob Parker). Four new transects have also produced results this season: Wolves Wood (Mark Nowers), Newsons Farm (Frances Bee), Barham picnic site (Nick Dickson) and Upper Abbey Farm (Trudy Seagon), bringing the total to 12 full transects and 3 single-species transects. Special thanks are due to all those transect walkers for their regular monitoring, which provides an objective abundance count as well as sitespecific observations, and flight times.

Trans. Suffolk Nat. Soc. 42 (2006)

Suffolk Natural History, Vol. 42


Annex A. Scarcity 2004 & 2005 for 34 species seen in Suffolk in 2005 % of 536 Tetrads Species in order of tetrads 2004 scarcity in 2005 0Â2


0Â2 0Â4 1Â3 6Â7

Tetrads % of 500 cf last* 2005 tetrads

1 2 7 36

Queen of Spain Frit. Purple Emperor Camberwell Beauty Swallowtail Dingy Skipper Clouded Yellow

1 1 2 4 13

0Â2 0Â2 0Â4 0Â8 2Â6

1Â07 0Â61 0Â39



Silver-studded Blue











White-letter Hairstreak White Admiral










12Â3 5Â8 6Â9 12Â1

66 31 37 65

Wall Green Hairstreak Purple Hairstreak Brown Argus

39 43 46 53

7Â8 8Â6 9Â2 10Â6

0Â63 1Â49 1Â33 0Â87

17Â4 26Â7

93 143

Small Heath Painted Lady

94 95

18Â8 19Â0

1Â08 0Â71

19Â0 16Â8 22Â6 29Â9 19Â8 30Â0 30Â6 37Â1 46Â3 36Â9 34Â5 42Â0 54Â3 43Â1 47Â9 50Â4 52Â8 54Â7 61Â9

102 90 121 160 106 161 164 199 248 198 185 225 291 231 257 270 283 293 332

Essex Skipper Large Skipper Small Skipper Small Copper Brimstone Ringlet Common Blue Orange-tip Gatekeeper Comma Holly Blue Red Admiral Meadow Brown Peacock Green-veined White Speckled Wood Large White Small White Small Tortoiseshell

107 121 135 144 163 179 188 244 249 267 281 285 294 302 302 307 316 317 334

21Â4 24Â2 27Â0 28Â8 32Â6 35Â8 37Â6 48Â8 49Â8 53Â4 56Â2 57Â0 58Â8 60Â4 60Â4 61Â4 63Â2 63Â4 66Â8

1Â12 1Â44 1Â20 0Â96 1Â65 1Â19 1Â23 1Â31 1Â08 1Â45 1Â63 1Â36 1Â08 1Â40 1Â26 1Â22 1Â20 1Â16 1Â08

* indicates the proportion of last years cover achieved in current year

Trans. Suffolk Nat. Soc. 42 (2006)


Barnham failing Poor migration year 2004 records were thin Encouraging Apparently spreading No real expansion Decline continues A good year Populations stabilising Poor migration year A good year

A good year

A good year A peak year

Still spreading



Annex B. Analysis - 1995 to 2005. A measure of Abundance - for residents and regular visitors. Survey from: to: Period: Tetrads:Species/Tetrad:

1995 1999 5 yrs 1089 15.4

Small Skipper Essex Skipper Large Skipper Dingy Skipper Clouded Yellow Brimstone Large White Small White Green-veined White Orange Tip Green Hairstreak Purple Hairstreak White-letter Hairstreak Small Copper Silver-studded Blue Brown Argus Common Blue Holly Blue White Admiral Red Admiral Painted Lady Small Tortoiseshell Peacock Comma Speckled Wood Wall Grayling Gatekeeper Meadow Brown Ringlet Small Heath

639 714 639 5 147 473 920 953 973 858 151 216 40 543 17 320 635 703 56 809 570 982 923 619 452 350 182 937 1002 669 359

2000 2001 2004 2005 2002 2003 2004 2005 5yrs 5yrs 1yr 1yr 1yr 1yr 878 865 338 448 530 500 11.9 11.8 8.5 9.4 8.4 10 Tetrads from which recorded 261 290 66 114 121 240 253 65 88 102 228 259 64 90 90 7 7 3 5 7 192 87 31 40 36 249 290 64 100 106 579 617 198 251 283 576 622 177 245 293 520 572 170 203 257 401 455 117 151 199 83 85 23 29 31 109 112 34 40 37 43 54 16 25 13

135 107 121 4 13 163 316 317 302 244 43 46 22

297 20 160 327 370 36 538 410 538 468 403 535 200 107 495 582 334 195

144 17 53 188 281 32 285 95 334 302 267 307 39 38 249 294 179 94

310 20 169 367 476 46 571 396 615 527 457 572 183 107 524 615 378 205

94 13 26 92 113 13 158 144 143 150 153 184 61 49 145 184 105 50

141 18 82 156 82 17 288 275 289 219 221 245 83 52 194 235 150 93

160 11 65 164 185 13 225 143 332 231 198 270 66 34 248 291 161 93


insecure variable spreading


stable settling cyclical spreading variable

infilling declining unclear


Notes Rare migrants excluded.

Trans. Suffolk Nat. Soc. 42 (2006)


Suffolk Natural History, Vol. 42

Annex C. Annual Report on Silver-studded Blue for 2005 Season 2005 was a late start by comparison with the past 2 seasons. A cool, wet spring protracted larval feeding, and the butterfly was not on the wing until 18 Jun, compared with 7 Jun in 2003/4. A summer interrupted by heavy rain spoiled survey effort as well as depressing the peak figures at most colonies. Relatively low temperatures reduced the prospects for colonising activity late in the summer. The Counts The main count at Minsmere had been planned for 20 Jun, and a team of volunteers counted the two main colony areas until it became clear that the population was predominantly male, and well short of its peak. Unfortunately the re-count two weeks later was hit by torrential rain, and the third attempt was past the peak, so the results were unsatisfactory. Most other colonies were adequately counted, although recorders had to make several visits to get reasonable results. An initiative to introduce mini transects at Minsmere got off to a poor start, but was trialled sufficiently to devise a workable plan for future years. Results The results for the season’s counts are tabulated below, and are generally less complete than usual. Although the results for Minsmere, Walberswick, Westleton Heath and Common, Upper and Lower Hollesley are not high, they do not give cause for concern. Furthermore, there is some encouragement from the recently established colonies at Parsnip Plantation and Rushmere Heath, both of which have shown a gentle increase in numbers. Furthermore, overall distribution maps for 2005 show records from 17 tetrads, which is the second highest count since 1995. On the other hand, there was a population crash at Purdis Heath, and just one butterfly at Wenhaston Blackheath. Although the numbers at Martlesham Heath are higher (377) the downward trend does give cause for concern. These 3 sites need heather management, and are dealt with individually below. Purdis Heath Visits by 3 separate recorders found no more than 6 SSB, and none were found on the adjacent Golf Course. This is a serious crash from the recent past: 2004:63, 2003:86, 2002:108, 2001:145. In his 2003 report to SWT, Neil Ravenscroft warned that the over-mature condition of the heather, the low proportion of Erica, and the absence of ant colonies all presented grounds for concern. It is salutary that just 2 seasons after this alarm, the colony is in crisis. A number of discussions and an on-site meeting were held to assess the strength of the ant colonies and to consider appropriate heather management plans for the forthcoming winter. It was felt that past forage harvesting had been the correct technique, but that an insufficient area of pioneer heather had been created. To enlarge the area suitable for egg-laying in 2006, forage

Trans. Suffolk Nat. Soc. 42 (2006)



harvesting will be undertaken to extend the width of each tract of cut heather. Additionally, a fresh tract will be cut to the south side of the footpath through the “main flight area”. Martlesham Heath The count of 377 includes one well-populated flight area where the heather is re-growing following an accidental burn, so the reality of a low count in other areas is somewhat concealed. The area in need of cutting is enormous and beyond the resources of the Martlesham Conservation Group. If English Nature funds can be released to enable forage harvesting in the (privately owned) airfield area, the colony will have a future, otherwise the prospects are not good. Wenhaston Black Heath For the third year in succession, the population has been barely detectable, and SSB have been noted only in the traditional flight area, even though other areas of pioneer heather are now available nearby. Habitat work by the Wenhaston volunteer group continues. Monitoring The results of the 2005 counts are summarised below: 2005 COUNTS Monitored Silver-studded Blue Sites listed geographically from the North Location

Grid reference Date

Blackheath Wenhaston Walberswick Comn NNR Aldringham Walks Westleton Heath NNR Westleton Common Westleton Football Pitch Minsmere Westleton Walks Minsmere Sawmills Minsmere Football pitch Minsmere Natterjack pond Minsmere SW Comp 1 Minsmere Pit Comp2 Minsmere SE Comp 3 Minsmere Comp 20 N Minsmere S Comp3 Minsmere Central Comp 3 Minsmere Powerlines Minsmere North Bridleway Minsmere Potbriggs Minsmere North Grimstones Minsmere E Comp 13 Minsmere Comp 13 track Minsmere Comp13 Tanktrap Dunwich Heath Comp 20 South

TM420749 TM491752 TM464612 TM4569 TM44306870 TM44406880 TM459689 TM452692 TM451691 TM451693 TM450694 TM457692 TM457691 TM446683 TM456693 TM453693 TM461683 TM468687 TM468689 TM462688 TM468681 TM464681 TM466683 TM468687 TM445670

07 29.06 01.07 29.06 03.07 03.07




Richard Havard Adam Burrows Rob Macklin Adam Burrows David Rous David Rous

1 26 179 137 175 25

10 38 39 77 15

47 368

0 37



20.06 Mel Kemp 20.06 Mel Kemp

07 David Sutton

Total 1 36 217 176 252 40 0 0 0 0 0 0 0 0 0 0 0 0 47 405 0 0 0 2 0


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Suffolk Natural History, Vol. 42

2005 COUNTS Continued Location

Grid reference


Gravel Pit Upper Hollesley MOD Lower Hollesley ‘A’ Lower Hollesley ‘B’ Lower Hollesley ‘C’ Rushmere Heath Martlesham Heath Parsnip Plantation Ipswich Golf Club, Purdis Purdis Heath Industrial Estate

TM449669 TM33344723 TM342465 TM343461 TM350460 TM202448 TM2445 TM32724579 TM208432 TM21204270 TM207419

11.07 02.07 02.07 28.06 14.07 10.07 11.07 07 06.07 06.07




David Mason 159 33 Richard Stewart 325 142 Richard Stewart 244 91 David Mason 22 2 David Mason 8 2 Phil Smith not split David Mason 17 1 Neil Sherman 0 0 Richard Stewart 6 0 Richard Stewart 47 20 2005 Totals: 1787 508

Total 0 192 467 335 24 10 377 18 0 6 67 2672

Annex D. Dingy Skipper Survey, 2005 Summary The 2005 survey continued the intensive study of 2004, refining our knowledge of the extent of the Dingy Skipper’s distribution. The new-found colony in the Archery area of King’s Forest was found to be flourishing, with a peak count of 115, and an expanded flight area. On the other hand, the established colony at RAF Barnham had a very poor showing, with just one Dingy Skipper seen in two separate visits. This abrupt change is probably related to the recently-introduced sheep grazing regime, and needs careful management, if the colony is to survive. Continued checks of former sites did not reveal any unexpected records, and there were only a few sightings in the Chalk Lane areas. A number of possible sites in peripheral areas were investigated this year, notably along the Cut-off Channel, where no Dingy Skipper were found, although the banks of the same waterway do hold good populations just a few miles into Norfolk. The population on the Devil’s Dyke remains strong, although this lies just outside VC26, i.e. in Cambridgeshire’s recording area. The very promising site at the Thetford Rifle Range was inspected, but no Dingy Skipper were found despite the apparently suitable habitat. The season was again later in the Brecks than in Cambs, and this was exaggerated by the cold wet spell in early May. The flight period became rather extended, and some Dingy Skipper were still flying in King’s Forest on 18 June All visits were conducted with the landowner’s consent, or along public rights of way. A total of 17 sites were visited during the 2005 flight period. Dingy Skippers were found only at the established sites, including an isolated, but stable colony at Center Parcs. The butterfly appears to be holding its own in a very limited area of the Suffolk Brecks, covered by just 5 tetrads.

Trans. Suffolk Nat. Soc. 42 (2006)



2005 Survey The Dingy Skipper was on the wing from late April elsewhere in UK, and on the Devil’s Dyke (Cambs/Suffolk border) by 2 May, but the Brecks population were again later. None were flying on 6 May, and the first definite record was from Wordwell on 14 May. The cool wet spell at the start of May had the effect of extending the flight period. This finished at Devils Dyke by 8 June (last sighting 28 May), yet they were still present in King’s Forest on 18 June. The survey involved 19 participants, and the main events were: 29 Apr 05 12 May 05 14May 05

Training at Barnham (Spring Survey Event). Survey along Cut-off Channel in Lakenheath area. Counts at Wordwell & Archery area, but nothing found at Chalk Lane or to the north east. 18 May 05 Count at Center Parcs, repeated by staff on 27May. 23 May 05 RAF Barnham survey – negative, repeated 3Jun – only one seen. 24/25 May 05 Surveys at Thetford rifle range 25 May 05 Chalk Lane; 2 seen. 30 May 05 King’s Forest; one seen west of road (first since Millennium survey). 6 to 31 May Negative searches made at Euston, Sketchfar, Marmansgrave, Barnhamcross, Berners Heath, also Shepherd’s Grove, Haverhill etc.

A grant from Awards for All enabled volunteers to be reimbursed for mileage undertaken during the survey. The sites visited are listed individually below, as active, defunct or for future investigation. ACTIVE COLONIES RAF Barnham [TL 8580/8680] – The first visit to the Barnham Training Area, in fair weather found not a single Dingy Skipper, even though they were flying elsewhere on that day. This is alarming, at what ought to be our strongest colony. Sheep now graze the training area, and 64 were in the Dingy Skipper area on that day. By arrangement, English Nature attended the next visit on 3 Jun to assess the impact of grazing on the sward. On that day, just one Dingy Skipper flew, and the flowering of the Bird’s-foot trefoil was late. King’s Forest (Wordwell) [TL834732] – This site recorded a maximum count of 16 on 27 May, and again the Dingy Skippers were flying further to the south and west than the main ride, extending their domain to include the sheltered glades to the west of the tree line. King’s Forest (Archery) [TL831737] – Only 300m north of the Wordwell site, but cut off by a forest compartment, lies an east-west track with good Bird’s-foot trefoil along the margins. This links to an area used for archery practice, part of which is kept mown. This year’s count co-incided with good weather and fresh emergences, and a team of 6 counted no less than 107 Dingy Skippers active on 14 May. On subsequent visits, the flight area was

Trans. Suffolk Nat. Soc. 42 (2006)


Suffolk Natural History, Vol. 42

found to extend even further east and west than the first survey, its northern limit being the mature coniferous edge at TL830739. The Bird’s-foot trefoil grows over a wide area, and appears to flourish under the mowing regime implemented for the archers. King’s Forest (Chalk Lane) [TL827752] – Numerous visits to this traditional site proved negative, although at least 2 were seen close to the heathland regeneration area on 25 May. The tree felling discussed last year with the Forestry Commission has not yet come to pass. The 2004 records of strays further east and north were not reproduced, despite several independent searches. Elveden (Center Parcs) [TL810805] – A site visit with Center Parcs Ecology Manager found at least 9 Dingy Skipper flying on 18 May, and staff revisiting on 27 May were able to find 15. The area mown as the bird walk will be managed with the Bird’s-foot trefoil in mind. DEFUNCT SITES King’s Forest (John O’Groats Cottages) [TL818737] – One Dingy Skipper was found on the track from the main road towards John O’ Groats Cottages, and this was the first sighting on the west of the B1106 since the Millennium survey. However, there is not much suitable habitat in this area, and the significance of one stray crossing the road should not be overstated (this point is only 200m from the edge of the Archery colony). Kings Forest South [TL7872/8073/8272SW] – Not specifically targetted this year, but no casual records received.. Barnhamcross Common [TL864811] – This site lies adjacent to RAF Barnham, and occasional strays are seen on the south edge of Barnhamcross Common, which lies in administrative Norfolk, but in Suffolk’s biological recording area. Several visits were made to the southern margin and the wider area of the common, but no Dingy Skippers were found. Marmansgrave Wood [TL8480] – An abundance of Common Blues in this area suggest that Bird’s-foot trefoil may exist along the footpath, but the bracken encroachment continues, and the former site may be considered defunct. A sheep-grazed area in the Elveden Estate’s Sketchfar domain has one promising looking corner at TL836801, which deserves a visit next year. Euston Quarry [TL896775] – This wonderful CWS has everything that ought to make a good Dingy Skipper site, including Bird’s-foot trefoil and a Common Blue colony. It was inspected early this year, on 8 May, but for the third year in succession, no Dingy Skippers were found. OTHER SITES (Inspected, with negative results) Cut-off Channel [TL7386] – During Norfolk’s 2004 survey for Grizzled and Dingy Skipper, both were found along the watercourse known as the Cut-off channel, which has a chalky double embankment along a nine mile stretch in Norfolk. Visits to the Suffolk stretch were made on 12 May (after finding DS flying in nearby Norfolk), but there was a shortage of Bird’s-foot trefoil, and nothing was seen.

Trans. Suffolk Nat. Soc. 42 (2006)



Thetford Rifle Range [TL8480] – This MoD site lies in Administrative Norfolk, but is in Suffolk’s biological recording area. It has plenty of Bird’sfoot trefoil in a suitably sheltered area, and was walked extensively on 24 May in poor weather and again on 25 May in hot weather. Although the habitat looked excellent, it was disappointing not to find any Dingy Skippers. Berner’s Heath [TL7977] – The northern edge of Berner’s Heath has plenty of Bird’s-foot trefoil along the rather exposed northern edge. It was visited twice (16 May in poor weather & 17 Jun in good conditions) without success. Sketchfar [TL836801] – See remarks above, under Marmansgrave Wood. Shepherd’s Grove [TL9872] – This area has some Bird’s-foot trefoil on the former airfield, not far from the planned IKEA development. It was surveyed on 8 Jun, but did not appear suitable for Dingy Skipper. Haverhill Industrial [TL6844] – This area (mainly just outside VC26) has Bird’s-foot trefoil, and had been suggested as a post-industrial site worth inspection. Three visits were made, but no Dingy Skipper were found. Annex E. White-letter Hairstreak for 2005 The White-letter hairstreak has now been accepted as a Suffolk BAP species, although the Species Action Plan has yet to be written. Its future is viewed with some concern at a national level, largely because of the uncertain consequences of Dutch Elm Disease. The recently published “The State of British Butterflies” presents its ten-year population trend as a loss of 63% in Britain. In Suffolk, we have been working so hard to unearth surviving colonies of this previously under-recorded insect, that distribution figures appear to show a substantial increase. The analysis at Annex B shows that the number of tetrads occupied by White-letter hairstreak has increased from 40 to 54 since the Millennium survey, but this apparent spread must be treated with caution. On the one hand, the butterflies are showing some adaptability in leaving elms infected by the disease, and they are moving on to younger suckers elsewhere. This adaptability could be an effective survival mechanism, but it also leaves dots on distribution maps at sites recently abandoned, and is thus misleading. Our volunteer recorders are also becoming more skilled at finding small colonies at the same time as the butterflies are becoming easier to find due to lower elm canopies and successive hot summers. That said, the White-letter hairstreak was recorded from 22 tetrads in 2005, including observations from 9 fresh sites. It is clear that the butterfly is surviving at many small sites spread across the county. We will continue to monitor its health in future seasons. Rob Parker 66 Cornfield Road Bury St Edmunds Suffolk IP33 3BN

Trans. Suffolk Nat. Soc. 42 (2006)


Rob Parker

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