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2010 BUTTERFLY REPORT ROB PARKER The year began with a relatively harsh winter, with persistent heavy frosts and strong winds which killed tender plants and will have had a significant impact on overwintering eggs, larvae & pupae. Nonetheless, spring butterflies appeared in reasonable numbers, and the first impression was that all was OK. In the longer term, the year has been something of a Curate’s Egg – good in parts, but very flat otherwise. Most of our common butterflies had a mediocre season, yet some of our BAP species had a really good year. In addition, this became the year of the Silver-washed Fritillary, with its welcome dispersal into East Anglia. Good recording effort has resulted in decent coverage for the first year of the next five-year period. Annexes A & B provide analysis of the season’s results and compare them with previous years. Weather Winter was colder and wetter than last year, with air frosts on 38 occasions, and worse than average judged by historic averages (see Table 1 below). Spring was cooler than 2009 and drier than average. The summer figures in the table reflect a wet summer with average temperatures and sunshine. Yet July was much drier than average, and triggered the dispersal of White Admirals and Silver-washed Fritillaries. Autumn was rather drab; slightly cooler & cloudier than average – and distinctly short on butterflies. Table 1. 2010 Weather for East Anglia

Season Winter 09/10 Spring Summer Autumn

Mean Temp Anomaly Sunshine Anomaly Rainfall

Anomaly

°C

°C

hrs

%

mm

%

2·5 8·8 17 10·3

-1·7 0·2 1 -0·3

172 544 571 309

99 120 98 95

211 75 177 163

144 55 118 94

Source: www.metoffice.gov.uk/climate/uk Anomalies are measured against the 1971 to 2000 averages. (as last year) Residents - Winners & Losers Most garden recorders remarked on the poor showing of their regular species. Although bright days in March and early April brought out Small Tortoiseshells, Peacocks and Brimstones in reasonable numbers, very few Red Admirals survived the winter. Summer never really arrived, and even Whites were less than abundant. Small Copper, Common Blue & Brown Argus all

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maintained average distribution, and even the Whites were less abundant than usual. Large Skipper did reasonably well, Small and Essex Skippers seemed less numerous and Essex Skipper was found in only 15% of tetrads surveyed. By contrast, it was a good season for some of our scarcer species – White Admiral, White-letter Hairstreak, Silver-studded Blue all did well. Monitoring the BAP Species There are seven Suffolk BAP priority species, including two in the “for study only” category. Silver-studded Blue The annual survey counted over 7000 SSBs – with good results at the larger sites, especially pleasing with an expanding colony in Minsmere’s reversion field, and at the southern edge of the Dunwich Forest, where the Westleton Heath population has quickly re-colonised a forest compartment felled by the RSPB specifically to allow heathland regeneration. The colony we translocated to Blaxhall common in 2007 also had its best-ever year, with a peak of 31 butterflies counted on the transect during the six-week period they were flying. At the other end of the scale, visits to Purdis Heath never found more than three, re-affirming the importance of extending our efforts to improve the deteriorating habitat before the colony is completely extinguished. Neil Ravenscroft’s 2009 survey highlighted the decline of the flight area over 20 years, and we have now triggered an emergency habitat restoration project for the benefit of this Ipswich heath. Dingy Skipper Was not found at RAF Barnham for the fifth year in succession, and the colony has probably been lost. Yet an unexpected find was made just a kilometre away, where a few were flying in a recently-planted compartment of the Thetford Forest. Once again, there were no sightings from the small isolated site at Center Parcs, and this too may have been lost.. In the King’s Forest, decent numbers are still breeding around the archery site, and there appears to have been some spread out to the east. A few were also found at the southern end of the forest, where felling has opened the rides to more sunlight. See Annex D for more detail. White-letter Hairstreak Was one of the species that had a good year. The short spell of hot drought days in July proved to be perfect for inducing White-letter Hairstreaks down from the elm canopy to find nectar at bramble and thistle. Six recorders managed to photograph them in gardens and at spots not known as established colonies, and a dedicated search re-discovered them at the SWT reserve in Bloodhill Quarry. See Annex E for more detail. White Admiral Also had a pleasingly strong year, with good numbers at many of the known sites, and no less than twelve reports of White Admirals dispersing to places not usually considered to host colonies. This year, it brought in 92 sightings,

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from 51 tetrads (almost 9% of surveyed squares, doubling last year’s counts). The colony in Bradfield Woods has now been present for six consecutive seasons. The situation here is more favourable than in the UK as a whole. One almost black specimen of var. obliterae was photographed by Jon King on the Hadleigh railway line walk, and another by Mervyn Crawford in Mildenhall woods. See Annex F for more detail. Grayling Is in general decline across Suffolk, and particularly so in West Suffolk, where all five 2010 Breckland casual sightings were singletons. Fortunately, it continues to fare well at its haunts in the Sandlings including Dunwich Forest, where it is now monitored on two new transects. See Annex G for more detail. The UK BAP list includes two further species for study and enhanced monitoring. In both cases, Wall and Small Heath, the larval host plant is grass. Wall Is in decline in the UK and in Suffolk. Lost from inland locations, its distribution is now restricted to well-drained sandy soils of low fertility, particularly down the east coast, with a lesser stronghold in the NW corner of the county. Under a Suffolk Naturalists’ Society initiative, Wall becomes the target in a single-species survey for 2011. In 2010, it was found in only 4% of the surveyed tetrads, and none were noted in West Suffolk. Small Heath Is in a less critical situation than the Wall, but is losing ground on farmland amongst fertilized grass. It was recorded from 234 tetrads in the last five-year survey (24% of 994 recorded tetrads), but numerical counts are falling at the few transect sites which still support it, and 2010 was slightly below average. Purple Emperor The introduced Purple Emperors were still flying in Theberton Woods, and on one occasion, three females were active together. However, there were no further appearances at Minsmere or elsewhere. Migrants After such an exciting Painted Lady invasion in 2009, this year was something of a let-down. 2010 was almost migrant-free, with just eight Clouded Yellow all year, and only a smattering of early Painted Lady – these did breed however, and there were eventually 100 sightings scattered across the county. Large White numbers were not high, although at least one small immigration was noted coming in from the North Sea. Silver-washed Fritillary Undoubtedly the highlight of the season was the spread of Silver-washed Fritillary from a couple of tentative footholds (2006 & 2009) to no less than nine places in Suffolk. Of these, six are woods with violets and some chance of providing breeding habitat. Essex, Cambs. and Norfolk all experienced this dispersal event, and there is hope that the species will stay – it has been considered absent from Suffolk since 1969.

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Unusual Sightings There were five Swallowtail sightings, extending from Milden in the south of the county to Beccles in the north. Most of these were known to be accidental releases of captive-bred specimens, and this makes it impossible to declare which of them might have been wild vagrants. Marbled White and Heath Fritillary both put in appearances in Ipswich’s Landseer Park, and as the latter must be the result of a misguided release, doubt is thrown on the validity of the first. One Long-tailed Blue was more likely to have arrived as a caterpillar in a packet of peas, than to have flown in on its own wings. These last three sightings have been excluded from the analysis (Annexes A & B). Early & Late Records Following another cooler, more “normal” winter, spring 2010 brought only one earliest-ever record – this of a Small Copper on 20 March. The autumn seemed to offer late nectar, but few butterflies took advantage of it, and cold weather terminated the season early. There were no latest-ever records for any species and the last few Red Admiral records petered out in mid November. The snow in December began an early cold winter. Recording and Geographic Coverage As the first year of a new five-year period, 2010 got off to a good start and a total of 575 tetrads were visited. 16 of these were some of the remaining “black holes” left over from the previous period. The British Trust for Ornithology contributed records from their Garden Bird Watch survey, and these extended our cover usefully. Some interesting records for White Admiral, White-letter Hairstreak and Silver-washed Fritillary were also added to the database. The area covered most thinly is still the agricultural land in High Suffolk, where both the human population and the butterfly density are inherently low. Targets for next year include the SNS Wall survey and monitoring the distribution of the declining Grayling and Small Heath. 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, including the introduced Purple Emperor, but excluding likely releases. The average number of species recorded per tetrad was 9·7, not bad given the shortage of migrants. Analysis The species that put in an appearance this year are shown in Annex A, in order of scarcity, with a direct comparison to last year’s turnout. Our most widespread residents were again reshuffled, with Small White just beating Meadow Brown as our most widely distributed butterfly. Red Admiral, in fifth position, did better than Small Tortoiseshell, Peacock or Comma. Brown Argus and Common Blue both did reasonably well, but without matching last year’s cover. Each species’ distribution relative to last year is expressed in the “c.f. last” column. Holly Blue continued its recovery and White-letter Hairstreak also picked up after a poor showing last year.

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Trends over a longer period are presented separately at Annex B for our 31 regulars. Surprisingly, the six that have achieved wider distribution in the past five years than in the Millennium Survey include four UKBAP species. White Admiral and White-letter Hairstreak, are genuinely expanding in Suffolk, and Silver-studded Blue has made several minor gains. The loss of the Dingy Skipper from two old haunts is offset by sightings in three tetrads elsewhere. Speckled Wood and Comma are also genuinely more widespread than a decade ago. However, that leaves 25 species apparently less widespread than in the Millennium survey – which must give pause for thought. In many cases the declines are substantial and real, even though the figures are distorted because recorders visited only 92% of the tetrads covered in the Millennium survey. To those thinking about the declines, the table at Annex B merits close study. Transects Analysis derived from distribution maps responds rather slowly to changes in a species’ health. The “index” derived from transect walks, on the other hand, gives a better readout of a species’ abundance in the current year, albeit at specific sites. The 18 full transects walked this year included new walks at Dunwich Forest and Arger Fen. Indices confirmed the long-term decline of several species including Common Blue, Small Heath and Grayling (now also monitored at Dunwich Forest).

Special thanks are due to Rob Macklin for his 20 year stint at North Warren, and Richard Stewart, who has concluded a ten-year run at Fynn Valley. All of the following achieved dedicated monitoring at: North Warren (Rob Macklin), Minsmere (Robin Harvey), Bradfield Woods (Steve Hunt), Center Parcs (Graham Hersey-Green), Cavenham Heath (Michael Taylor), Walberswick (Will Russell), Spring Lane (Rob Parker), Combs Wood (Colin Cripps), Ramsey/Hintlesham and Wolves Wood (Mark Nowers), Newsons Farm (Frances Bee), Upper Abbey Farm (Trudy Seagon), Alton Water (Simon Waters), Manor Farm (Brenda Hudson) ,Tythe Farm (Peter Vincent), Dunwich Forest 1&2 (Dayne West) and Arger Fen (Kerry Vaughan). Single-species transects for Purple Hairstreak (Steve Hunt) and Silver-studded Blue (Terry Peake) also produced useful results. In almost every case, additional volunteers (not named individually) assisted the lead walker. Conservation Advice Site-specific butterfly conservation advce has been provided to the Sotterley Estate, the SWT reserve at Cubbitt’s Pit in the Bloodhill Quarry and to the management at Pakenham Wood. All three sites host BAP species, and White Admiral, White-letter Hairstreak and Silver-washed Fritillary put in appearances during the advice & monitoring phase.

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Annex A. Scarcity for 34 species seen in Suffolk in 2010. Tetrads per Species – 2009 & 2010 (Species listed in order of scarcity in 2010) % of 645 Tetrads tetrads 2009 Species 0.5 0.0 0.3 0.0 0.8 8.8 0.2 2.6 5.6 2.5 8.4 4.0 6.4 8.7 16.4 15.5 19.8 69.3 26.2 30.9 29.1 30.9 38.6 23.7 41.6 37.8 63.7 61.7 60.8 54.4 63.3 43.9 54.9 72.7 67.3 65.9

3 0 2 0 5 57 1 17 36 16 54 26 41 56 106 100 128 447 169 199 188 199 249 153 268 244 411 398 392 351 408 283 354 469 434 425

Marbled White Swallowtail Purple Emperor Camberwell Beauty Dingy Skipper Clouded Yellow Silver-washed Frit Silver-studded Blue Wall White-letter Hairstrk Grayling White Admiral Green Hairstreak Purple Hairstreak Essex Skipper Small Heath Brown Argus Painted Lady Small Skipper Large Skipper Small Copper Brimstone Common Blue Holly Blue Ringlet Orange-tip Speckled Wood Small Tortoiseshell Green-veined Wht Comma Peacock Red Admiral Gatekeeper Large White Meadow Brown Small White

Tetrads % of 575 *cf 2010 tetrads last See Note 1 See Note 2 1 0.2 2 0.3 4 0.7 8 1.4 9 1.6 15 2.6 25 4.3 26 4.5 42 7.3 51 8.9 51 8.9 66 11.5 88 15.3 100 17.4 111 19.3 125 21.7 161 28.0 176 30.6 190 33.0 195 33.9 222 38.6 231 40.2 250 43.5 266 46.3 281 48.9 282 49.0 292 50.8 299 52.0 305 53.0 320 55.7 326 56.7 344 59.8 353 61.4 384 66.8

0.56 n/a 0.90 0.16 10.10 0.99 0.78 1.82 0.87 2.20 1.40 1.32 0.93 1.12 0.97 0.31 1.07 0.99 1.13 1.10 1.00 1.69 1.05 1.22 0.77 0.79 0.84 0.96 0.84 1.27 1.03 0.82 0.91 1.01

Remarks

Theberton only Origin unknown 3 tetrads in King's Forest Poor migration year Impressive dispersal Decline continues

A very strong showing

Poor migration year

Poor year Slight recovery

Poor spring brood Poor showing

Notes: 1. Heath Fritillary & Marbled White releases not shown above 2. Swallowtails escaping from captivity masked wild vagrant numbers *cf last Indicates the prorortion of last year's cover achieved in the current year 34 species seen in Suffolk in 2010 (including introduced Purple Emperor) 37 species total (including Swallowtail & probable releases)

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Annex B. ANALYSIS – 2002 to 2010 A measure of Abundance – for residents and regular visitors 2004 2008

2005 2009

2006 2010

5yrs 5yrs 5yrs 868 879 918 12·1 12·6 12·7 Tetrads from which recorded Small Skipper 322 349 362 Essex Skipper 267 281 296 Large Skipper 295 325 347 Dingy Skipper 8 8 8 Clouded Yellow 111 119 104 Brimstone 317 368 394 Large White 599 637 683 Small White 606 657 685 Green-veined White 552 594 632 Orange Tip 439 480 522 Green Hairstreak 88 103 108 Purple Hairstreak 120 123 116 White-letter Hairstreak 70 75 81 Small Copper 341 371 369 Silver-studded Blue 20 21 21 Brown Argus 193 230 215 Common Blue 383 402 404 Holly Blue 419 454 502 White Admiral 61 65 68 Red Admiral 577 640 655 Painted Lady 448 472 403 Small Tortoiseshell 621 655 644 Peacock 532 585 621 Comma 475 526 557 Speckled Wood 565 608 636 Wall 163 160 136 Grayling 107 100 95 Gatekeeper 504 558 593 Meadow Brown 591 648 699 Ringlet 397 438 473 Small Heath 209 229 236

5yrs 994 13.1

5yrs 1003 13.4

390 296 412 8 118 442 785 775 718 552 113 128 79 376 22 260 475 504

411 292 439 8 118 461 806 799 731 565 119 147 83 402 21 292 505 498

71 699 604 698 700 635 724 120 104 663 789 528 234

79 720 615 701 714 663 720 115 108 701 805 571 241

Survey from: to:

2002 2006

Period: Tetrads:Species/Tetrad:

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Annex B. ANALYSIS – continued Survey from: to:

2006 2007 2008

2009

2010

Period: Tetrads:Species/Tetrad:

1yr 557 9·4

1yr 509 9·1

1yr 549 9

1yr 645 10.3

1yr 575 9.7

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

158 100 161 4 55 176 305 296 212 221 36 44 35 163 15 86 203 179 39 369 271 269 282 281 288 44 52 261 335 210 95

110 83 124 2 29 174 276 303 248 205 49 30 23 159 15 90 128 190 23 338 180 197 288 243 291 27 32 236 294 171 87

125 99 131 2 5 157 343 305 307 236 35 33 24 145 15 38 128 197 32 289 68 241 307 300 317 28 37 281 361 246 84

169 106 199 5 57 199 469 425 392 244 41 56 16 188 17 128 249 153 26 283 447 398 408 351 411 36 54 354 434 268 100

161 88 176 4 8 195 344 384 292 266 51 66 26 190 15 111 222 231 51 320 125 282 305 299 281 25 42 326 353 250 100

Trend

Weak Migrant variable

Stable Gaining Stable

Doing Well Migrant variable Decline checked

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Annex C. Annual Report on Silver-studded Blue for 2010 Season The first sightings of 2010 came in mid June, slightly later than average, and extended to the third week of August. This made a slightly shorter flight period than usual, peaking with well above average numbers early in July. Positive Developments Continuing consolidation on the pioneer heather of Minsmere’s reversion field brought a new high count of 1052, making it one of our strongest colonies. A small new colony has become established in the compartment at the SW corner of Dunwich Forest (TM461702) felled by RSPB to allow heathland regeneration. That site lies adjacent to Westleton Heath NNR, and the SSBs have spread to clumps of bell heather that were previously growing in the shade of conifers. Blaxhall Common The transect walk at Blaxhall Common found up to 24 Silver-studded Blues on the wing over a six week period from 11 June to 25 July. This is a higher number for a longer flight period than last year, which is encouraging. A separate search on 22 June found some off the transect route and just into TM3856, the next tetrad to the east. Results of Annual Count All the main sites were counted, mostly close to the population peak, although a number of the small sites were missed. A total of 37 out of 48 sites were counted, and the resulting total figure of 7124 was the highest since this counting format was adopted in 2004. At 130% of the 2006 datum, that reflects a successful count of an excellent year. Most colonies are in good health, but three remain where there is longstanding cause for concern. In addition, serious heather encroachment at Minsmere Potbriggs needs to be tackled urgently. Weak Colonies. The three colonies about which concern has been expressed since 2005 are Purdis Heath, Martlesham Heath and Blackheath, all of which produced low counts in this generally strong season. The miserable count of just four at Purdis Heath served as a trigger to initiate an emergency habitat restoration programme, which got underway in December 2010. Tabulation The results of the 2010 counts are tabulated on the next page Of the 37 colonies successfully surveyed, four were unoccupied. The total count of 7124 represents 130% of the 2006 datum, making 2010 an excellent year.

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BUTTERFLY REPORT 2010

Location Blackheath Wenhaston Walbers NNR, Newdelight Dunwich Forest Westleton Heath NNR Westleton Common Westleton Football Pitch Minsmere Reversion Field Minsmere Sawmills Minsmere Football pitch Minsmere Natterjack pit 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 N. Grimstones Minsmere Gravel Pit Aldringham Walks Blaxhall Common UHC 3d Upper Hollesley MOD SCDC Lower Hollesley ‘A ‘ Lower Hollesley ‘B ‘ Lower Hollesley ‘C ‘ LHC compt 1e Firebreak LHC compt 8c Martlesham Heath Parsnip Plantation Ipswich Golf Club Purdis Heath Industrial Estate

Grid Ref.

Date

Observer

TM420749 23/08 R. Havard TM451727 1/7 W. Russell TM461702 2/7 M. Kemp TM4569 2/7 W. Russell TM443687 27/6 D. Rous TM444688 27/6 D. Rous TM451689 28/6 M. Kemp TM452692 28/6 M. Kemp TM451691 28/6 M. Kemp TM451693 1/7 M. Kemp TM450694 1/7 M. Kemp TM457692 1/7 M. Kemp TM457691 1/7 M. Kemp TM446683 2/7 M. Kemp TM456693 1/7 M. Kemp TM453693 1/7 M. Kemp TM461683 28/6 M. Kemp TM462688 28/6 M. Kemp TM449669 1/7 M. Kemp TM464612 3/7 R. Macklin TM377566 27/6 S. Thacker TM337480 5/7 D. Mason TM333472 5/7 D. Mason TM335471 5/7 D. Mason TM342465 30/6 R. Stewart TM343461 30/6 R. Stewart TM350458 30/6 D. Mason TM346462 30/6 D. Mason TM350456 30/6 B. Calvesbert TM338468 5/7 D. Mason TM2344 11/7 P. Smith TM327458 5/7 D. Mason TM208432 ~ N. Sherman TM212427 11/7 S. Gough TM207419 1/7 J. Dowding

89 ♂

Total

5 14 32 76 365 18 888 660 317 74 9 445 404 344

1 4 11 18 58 3 164 208 73 53 3 223 195 122

6 18 43 94 423 21 1052 868 390 127 12 668 599 466 ~ ~ 1 881 5 112 31 0 141 6 124 529 126 10 6 42 139 69 0 4 111

1 0 630 251 4 1 71 41 26 5 0 0 109 32 3 3 114 10 468 61 97 29 8 2 6 0 28 14 not split 61 8 0 0 2 2 53 58

Sites counted: 37 of 48 (unsurveyed sites omitted from this table)

2010 Totals:

5332

1653

7124

Good year datum

2006 Totals:

3617

1438

5470

This year as a % of 2006:

130%

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Annex D. Dingy Skipper Survey, 2010 Overview The Dingy Skipper appears to have been permanently lost from the formerly strong site at RAF Barnham, and from the smaller colony at Center Parcs Elveden. This year’s survey shows that the colony in King’s Forest is still breeding in the area around the Archery ranges, and flying more widely in the forest. Nonetheless, with this as the only remaining colony in Suffolk, there is a strong possibility that it will be lost unless the right habitat is preserved. Fortunately, the Forestry Commission is being very co-operative, and has undertaken felling and clearing operations around the Wordwell ride to benefit the bird’s-foot trefoil and to create suitable areas for egg laying. 2010 Survey This year’s survey involved 23 recorders, and 39 man-days, but searches at Center Parcs and RAF Barnham again failed to find any Dingy Skippers. Seven were noted on the county border along the Devil’s Dyke on 29 Apr, and the first sighting in the King’s Forest was on 10 May (a week or 10 day’s delay is normal). A high count of 30 was achieved in good weather on 21May. The latest sightings were in the fine weather of 2/3/4 June. Yet another year without any sightings at RAF Barnham or Center Parcs strongly suggests that the Dingy Skipper has been extinguished at these two sites, leaving the King’s Forest as the only remaining Suffolk population. The sites visited are listed below, with more detail. This year’s effort was again focussed on defining the breeding area within the King’s Forest, with a view to extending the suitable habitat. RAF Barnham TL8580/8680 A comprehensive search was made in suitable weather on 25 May, but not a single Dingy Skipper was seen. Some bird’s-foot trefoil was present, and although some of the habitat looked suitable, most of the former flight area is shaded out. It seems almost certain that the Dingy Skipper has been lost from the SSSI. Last seen here in 2005. An unexpected sighting was made nearby though, when Sharon Hearle found four flying in a recently re-planted compartment of the Thetford Forest, just 200 m NW of RAF Barnham’s boundary fence (TL848808). Center Parcs, Elveden TL810805 This isolated colony existed on a small site that has been losing its suitable habitat to a build up of coarse grass. The cutting & rotovation work has not really created significant patches of bird’s-foot trefoil. Center Parcs staff visited the area regularly in May, without seeing any Dingy Skippers, and a BC search in good weather on 25 May, found nothing. Last seen here in 2006. In King’s Forest (overall): First found 10 May (nine days later than 2009). Best count: 30 on 21 May. Latest sighting: 4 Jun. Extent: From Wordwell to Chalk Lane, but confined to two tetrads, despite strays to the east of the Archery area.

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King’s - Chalk Lane area (TL 8275 & 8374) A total of seven were seen on Chalk Lane and the parallel path just north of it, which is more than in recent years. King’s - Archery Restricted area TL833737 The secluded open area between the mature beech to north and plantation to south seems to be the main breeding site (TL834739). The flight area extends along the east-west ride (204) south of the Archery hut to TL838734. The north-south conservation ride (205) bounding the archery restricted block was again in use as a regular flight area. The highest one-day count in this area was 26 on 21 May. King’s – Griffin’s Covert (East of Archery area) Occasional sightings were again made at the edge of Griffin’s Covert. The ride extends east into the next tetrad, but none were noted that far east. King’s - Wordwell area TL834733 Conservation felling has widened the main ride by 30m, and this allows more sunlight into the strip where the bird’s-foot trefoil grows. The stumps have yet to be lifted, and although 2 Dingy Skippers were seen at the corner of the rough ground, there was no evidence that the Wordwell rides are still a breeding area. There was only one in 2008, and it is some years since they were present in numbers. King’s – West of B1106 There was just one sighting to the west of the road this year. Annex E. White-letter Hairstreak – 2010 Following a poor season last year, 2010 turned out to be an excellent year for White-letter Hairstreak, with sightings in 26 tetrads (4·5% of the surveyed area). At many regular sites they were seen in higher-than average numbers, often out of the canopy and taking nectar from bramble or thistle. A few new squares brought the five-year total up to 83 tetrads, or 7·6 of the whole county. This is rather pleasing for a UK BAP species which is declining in other parts of UK. It is worth noting though, that presence in one year does not necessarily indicate a stable colony; indeed, it can often be difficult to trace the source of an unexpected sighting, as the butterfly may simply be searching for a new home. The future of the White-letter Hairstreak in Britain is still viewed with concern because of the long-term consequences of Dutch Elm Disease. Yet it remains an under-recorded species that can be found in most places where elm survives - whenever intensive effort is put into a search. In Suffolk, it frequently turns up on elm in roadside hedgerows, where they are merely transient populations as distinct to well-established colonies. In other cases, they can re-appear at places where they have not been seen for a decade or more, such as happened at the SWT reserve in Bloodhill Quarry.

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Annex G. Grayling 2010 Added to the UK BAP Priority species list in 2007, the Grayling has lost 45% of its UK distribution over the past 30 years, and is now essentially a coastal species. Losses have been no less dramatic in Suffolk, and it is now very localised in its favourite Breckland haunts and extremely rare in Mid Suffolk, although it remains widespread in the Sandlings. The Grayling is an insect of dry sandy grassland, and has a generally coastal distribution. It also has a fondness for conifers on dry sandy heathland, and can still be found in the Brecks as well as the margins of Dunwich, Tunstall and Rendlesham forests. Formerly, it was regularly found in the general countryside too, but the clay soil of High Suffolk no longer supports it, and the distribution maps have thinned out, with few sightings outside of the prime areas of Suffolk Coast & Heaths District. The trend illustrated in recent years continues, and the colonies in the Brecks are isolated. In 2010 Grayling was found in just 7·3% of the county, rather less than last year. Although numbers are holding up in the Sandlings, a gentle long term decline is evident in the Brecks and the Cavenham Heath transect recorded only three Graylings all year. Two new transects have been started by SWT in the Dunwich Forest, and these will assist in monitoring Grayling populations (just as the Fynn Valley transect has closed). Annex F. White Admiral 2010 White Admiral continues its expansion in Suffolk woodlands. It has been noted in 78 tetrads (over 7% of the county) in the past five years, compared with just 13 (1%) in the 1983–1985 survey. The situation here is more favourable than in the UK as a whole, where its decline resulted in its being added to the UK BAP priority list in 2007. It inhabits damp woods with plenty of honeysuckle, and seems to have settled recently in several smaller woods that are not longstanding colonies. It is known that unofficial releases have been conducted in Dunwich and Tunstall Forests over a period of years (and probably in Theberton Woods too). Over the same period, climate change appears to have had a beneficial effect, and second generation emergences have been noted in good years (but not 2010). Progressive recording efforts have resulted in an increase in the tetrad count, but not all of the sightings indicate permanent colonization. Nonetheless, the past five years have produced good numbers, and it is encouraging to have a UK BAP species doing so well in Suffolk. In 2010, White Admiral was recorded from 51 tetrads (8·9% of the 575 covered) – almost double last year’s performance.

Trans. Suffolk Nat. Soc. 47 (2012)

2010 BUTTERFLY REPORT  

Rob Parker

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