2013 BUTTERFLY REPORT by Suffolk Naturalists' Society

BUTTERFLY REPORT 2013

2013 BUTTERFLY REPORT Bill Stone and Rob Parker By way of a brief overview, 2013 was a wonderful year for the majority of butterfly species. It was a year of unexpected recovery with the fine long lasting summer weather allowing several species to rebuild their numbers after the disastrous butterfly year of 2012. Everyone will remember it as a great Clouded Yellow year and, hopefully, most of you will have spent some time watching this wonderful migrant butterfly. The Silver-washed Fritillary continued its range expansion and its numbers swelled in the key woodlands too. In addition, some incredible counts of Peacocks, Small Tortoiseshells and both Small and Large Whites were enjoyed during the summer. By contrast the Wall failed to show any signs of recovery and appears to be slipping slowly off the Suffolk butterfly list. Overview of the UK weather in 2013 The annual statistics for the UK in 2013 were generally near average. However, many meteorological records were broken. A late winter and exceptionally cold spring, with unseasonably late snowfalls led into a long warm and sunny summer. October and December saw Atlantic storms that brought rain and at times very high winds, causing widespread disruption. The UK mean temperature of 8∙8 °C was 0∙1 °C below the 1981–2010 average. This is identical to the 2012 value. March was the equal second coldest March for the UK on record. Both March and spring overall were the coldest since 1962. In contrast, July was the third warmest in the series and it was the warmest summer since 2006. The July heat-wave was in marked contrast to the run of recent poor summers from 2007–2012. The UK annual rainfall total of 1086 mm (94% of average) was drier than average but not exceptionally so. May, October, and December were the only months to record above average rainfall for the UK. In both October and December, some parts of the UK received over twice the normal amount of rainfall for the month, and it was the wettest December on record for Scotland. Overall for the UK, it was a sunnier than average year (104%), but again not exceptionally so. It was the sunniest July since 2006 and the third sunniest July in the series from 1929. Table 1. 2013 Weather for East Anglia Season

Mean Temp

Winter 12/13 Spring Summer Autumn

Deg C 3∙6 7∙2 16∙9 11∙2

Anomaly Sunshine Anomaly Rainfall Deg C -0∙8 -1∙9 0∙5 0∙3

hrs 161∙5 453∙9 649∙8 321∙1

% 87 97 110 99

mm 175∙9 125∙9 105 194∙6

Anomaly % 119 92 65 108

Source: www.metoffice.gov.uk Anomalies are measured against the 1981–2010 averages.

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

Residents â&#x20AC;&#x201C; Winners & Losers (See Annex A for Scarcity of Species and Annex B for Long term trends for residents and regular visitors) The 2013 season began typically with a hibernator in the form of a Small Tortoiseshell seen on 1 January. By the end of the February, several records for the other hibernating species of Peacock, Red Admiral and Brimstone had also been received. The very cold winter clearly had an impact on the traditional spring butterflies with the majority of the first Orange-tip and Green-veined Whites records being 2â&#x20AC;&#x201C;3 weeks later than normal. This was a trend that seemed to be reflected across the UK. Speckled Wood also seemed to have been affected by the late spring and the year did not really allow for a full recovery for this species. Concerns were raised in 2012 regarding Common Blue, Brown Argus and Holly Blue. Both Common Blue and Brown Argus appear to have undergone a slight recovery with stronger later broods noted. Analysis of the records suggests that Holly Blue had a good spring brood but that the summer brood was poor. This clearly has implications for the species in 2014 and the position will need to be closely monitored. The long hot summer allowed the grass loving species to sustain their numbers and some exceptional counts of both Ringlet and Meadow Brown were received. Early & Late (See Annex C for full list of Earliest and Latest dates) This year saw five species with new dates. Given the fantastic year for Clouded Yellow it seemed apt for this species to share in the changes with one seen flying on 23 April 2013. The previous earliest was 27 April 1997. A Purple Hairstreak was seen on 3 June 2013, beating the previous record of 13 June 2011 by well over a week. The Orange-tip enjoyed a slightly longer flight season with several Suffolk records received well into July resulting in a new late record of 21 July 2013. Clearly, the long summer had a significant impact on this species. It is worth noting that at the 2014 BC Recorders Meeting it was revealed that a number of southern counties recorded Orange-tip into late August and early September. Were these late emerging individuals or perhaps evidence of a rare second brood? The incredible weather also helped lengthen the flight season for Silver-washed Fritillary and the latest date was extended to 26 August 2013 from 18 August in 2012. Finally, a late Meadow Brown record of 8 October 2013 reinforced the impact that the summer had on our butterflies. The previous latest for this species was two days earlier on 6 October in 2005. Migrants The year saw some good records for Painted Lady. This species received 392 records and was recorded in 222 tetrads. The year also proved to be an excellent one for Clouded Yellow with 329 records received covering 131 tetrads. Several counts in excess of 20 were made at the coastal locations of Landguard, Bawdsey and East Lane. Double figure counts were also received from inland sites demonstrating that good numbers penetrated well into west Suffolk rather than just on the coast. (See Fig. 1. 2013 distribution map for Clouded Yellow)

Trans. Suffolk Nat. Soc. 50 (2014)

BUTTERFLY REPORT 2013

Figure 1. 2013 Distribution map for Clouded Yellow. However, in respect of true rarity value Suffolk was fortunate to have five records of Long-tailed Blue with singles at Dunwich (11 August) and East Lane (8 October) and then singles on three consecutive days at Landguard Bird Observatory (6, 7 and 8 October). The Suffolk records appear to reflect what had been seen elsewhere in England with true migrants being recorded in August and their progeny being seen following emergence in late September and October. Unusual Species Exciting news was received when Chalkhill Blue was found in good numbers at a site (SSSI) in the west of the county in August. In addition, a single butterfly was seen flying along the railway embankment close to the A14 near Higham (20 August). It appears that the main site, albeit newly discovered, appears to be an established colony and on a suitable chalk habitat. In 2013, this species had a strong season and strayed far and wide. Significant dispersal was also noted in Cambridgeshire so it could be that this butterfly will appear at other suitable chalk land sites in west Suffolk in 2014. Two records (3, 21 August) of Marbled White were received from the extreme west of the county. This species is known to be a strong flyer and one that will wander so the 2013 records could relate to Cambridgeshire individuals exploring new areas. The population in Landseer Park, Ipswich was still present and butterflies were seen on the wing between 8 July and 9 August. Although numbers were lower (max day count of six) than last year,

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

breeding was noted with several records of egg laying females being received. As in 2012, the population was spread over two tetrads in Landseer Park but this year a record was also received from a third tetrad adjacent to the park. Interestingly, a record of a single Marbled White was also received from a garden in Martlesham on 22 July. Three records of Swallowtail were received during the year. One, presumably a wanderer from the east Norfolk population, was seen at Burgh Castle on 30 June. A second was recorded in the vicinity of Orford Lighthouse on 6 August and based on a photograph was likely to have been a female of the European form ssp. gorganus. Finally, a third of unknown origin was recorded in central Ipswich on 18 July. Other species of interest Exploratory work for Purple Emperor in Suffolk was undertaken in 2013 by Liz Goodyear and Andrew Middleton of the Hertfordshire and Middlesex Branch of Butterfly Conservation with sightings made in July in woodland in TL65. Work already carried out in Cambridgeshire and Essex had confirmed this species moving closer to Suffolk. Away from the introduced population at Theberton Woods, another record was received for a single butterfly at Bradfield Woods and another not far from Halesworth. It is entirely feasible that the Purple Emperor can be found in any suitable mature woodland in Suffolk and it is hoped that through Liz and Andrewâ&#x20AC;&#x2122;s work more records will be forthcoming in the future. 2013 was another great year for Silver-washed Fritillary with 88 records from 31 tetrads. This is opposed to 64 records from 24 tetrads in 2012. The hot July coincided with the flight period and some exceptional counts were made. As mentioned above a new latest date was also achieved extending the Suffolk flight season by eight days. A number of observations were also made of Silver-washed Fritillary flying strongly over arable fields, along railway embankments and in gardens close to mature woodlands. These sightings suggested that the butterfly is on the move and continuing to expand its range. (See Fig 2. 2013 distribution map for Silver-washed Fritillary). Suffolk Biodiversity Action Plan â&#x20AC;&#x201C; Priority Species Seven species of butterfly occurring in Suffolk are deemed as UK BAP priority species. These are listed below. See http://www.suffolkbiodiversity.org/ biodiversity-action-plans.aspx Dingy Skipper The Dingy Skipper enjoyed a strong season in 2013. The main organised counts on the 15 and 16 May were again too early. But, a count on the 26 May in the Kings Forest resulted in 83 Dingy Skippers being found and it was good to see that the butterfly had extended eastwards within the forest. Ridewidening work and a good spread of birds-foot trefoil also seemed to have helped the Dingy Skipper this year. It was found again on Thetford Heath and despite long term absences it was also found again at RAF Barnham and within the Elveden Center Parcs complex. (See Annex D for more detail)

Trans. Suffolk Nat. Soc. 50 (2014)

BUTTERFLY REPORT 2013

Figure 2. 2013 distribution map for Silver-washed Fritillary. Silver-studded Blue The Silver-studded Blue was seen in 15 tetrads with 107 records being received. The organised count resulted in some excellent totals being achieved with 27 out of 45 count sites being visited. A total figure of 6184 butterflies was the reward. However, no Silver-studded Blues were recorded from Walberswick NNR. It is unknown why this colony has been lost as the Bell Heather remains in a suitable condition and with appropriate habitat management still in place. Good news, however, came from the trans-located colony at Blaxhall. Here, not only has the population survived but it has been seen to have gone from strength to strength. (See Annex E for more detail) White-letter Hairstreak Always a difficult butterfly to see this year saw a slight increase on 2012. Favorable weather conditions and hot temperatures allowed a number of observers to watch and photograph this species nectaring on brambles and thistles rather than the usual brief glimpses of males spiraling high in the tops of elms. (See Annex F for more detail) White Admiral This species enjoyed another relatively stable year allowing it to establish itself further in known colonies. As with Silver-washed Fritillary a number of White Admirals were seen flying away from known sites and were also seen flying though gardens. It was found in four new tetrads and some very high counts enjoyed. (See Annex G for more detail)

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

Grayling This species showed a very slight increase in 2013 with it being seen in an additional twelve tetrads. Again, the majority of the records were split between the east coast Sandlings and the favored Breckland areas. Of interest was a record of a single Grayling at Bradfield Woods on 11 August. (See Annex H for more detail) Wall The Wall, in 2012 was seen to have its range reduced even further with the Suffolk population being squeezed into several pockets along a narrow strip on the east coast. Sadly, 2013 showed no real positive development in this situation. One key area remains the trinity of Bawdsey, East Lane and Shingle Street. However, in 2013 this area was subject to extensive work by the Environment Agency and contractors undertaking ground work for the landing of offshore wind farm cables. Despite a small number of Walls being reported in the latter part of the season it will be left to records from 2014 to properly address the impact in the area. (See Annex I for more detail) Small Heath Despite its name, the Small Heath is not confined to heath land. It is highly adaptive and can be found in a variety of grassy habitats including woodland rides but the key requirement is a short sward of fine grass species. During the year it was pleasing to hear that this species had appeared on a number of new conservation sites especially those being managed for Common Blue and Brown Argus. That said, it showed a very small decline against 2012 and it remains a species that requires close monitoring. (See Annex J for more detail) Recording and Geographic Coverage. In 2013, over 19,000 records were received, recording 37 species of butterfly and covering 637 tetrads. Given that Suffolk has 1089 tetrads that meant that the records received related to almost 60% of Suffolk. Most years, we average just over 500 tetrads being visited so it looks like the good weather encouraged us all to explore a bit more. As you may be aware, Butterfly Conservation (BC) operate a general recording scheme known as “Butterflies for the New Millennium” or BNM. This scheme operates over a five-year period for Britain and Ireland in order to assess change, inform conservation and stimulate research. The current BNM survey runs from 2010–2014, so 2013 represented the fourth year of the current five year period. Over the last four years (2010–2013) a total of 946 Suffolk tetrads have been visited and butterflies recorded. With 1089 tetrads in Suffolk that leaves 143 tetrads without any butterfly records being received over the last four years. These “black holes” are scattered across the county with the weakest area remaining the agricultural land in High Suffolk. It is worth noting that over 4,000 records alone were received from the Big Butterfly Count which ran between 20 July and 11 August. Included within these records were sightings for several tetrads for which either no previous records or only minimal records existed. Other online recording schemes also

Trans. Suffolk Nat. Soc. 50 (2014)

BUTTERFLY REPORT 2013

provided valuable records and it was interesting to note how advances in social media and smart phone “apps” are beginning to impact on how individuals record and submit their sightings. Species Maps Distribution Maps for individual species have been prepared for our 31 regular species, and these are available for reference as required. With the high number of tetrads visited in 2013 and the incredible number of records received the average butterfly species per tetrad for 2013 increased to 10∙9. This equates to the highest single year count in ten years. To put that into context the four year period (2010–2013) of the current BNM survey period gives us an average of 13∙1 species per tetrad. Analysis The 37 species of butterfly recorded in 2013 are shown in Annex A, in order of scarcity, with a direct comparison to last year’s statistics. The “white” butterflies had a very good year with Large White being the most numerous Suffolk butterfly species of 2013 appearing in 76% of the tetrads for which records were received. The second most numerous butterfly species was Small Tortoiseshell closely followed by the Peacock and Small White. It is interesting to note that numbers for all of these four species were swelled during the year with arrivals from Europe. Last year’s most abundant butterfly, the Meadow Brown, also had a reasonable year along with Ringlet and Gatekeeper. At the other end of the table, Dingy Skipper enjoyed a better year appearing in seven tetrads an increase of four on 2012. The hairstreak species fared differently with very slight increases for both Purple and White-letter but a slight decrease on the previous year for Green Hairstreak. Both Common Blue and Brown Argus are shown to have made increases on 2012 but both Small Copper and Small Heath show a slight drop. Trends over a longer period are presented separately at Annex B for our 31 regular species. The latest rolling five year figure (2008–2013) cover 998 tetrads and show an average of 14∙3 species per tetrad. Transects Analysis of transect results gives a sharp view of trends, and 2013 results have confirmed the general recovery from 2012, with most all-species transects recording better than average counts. The new transects at Knettishall Heath and Purdis Heath came on stream as planned, and were joined by another at Sizewell Belts. This brought our total up to a new record – 22 full and three single-species transects. Thanks are due to the following, who put in dedicated monitoring effort at: North Warren (Dave Thurlow), Minsmere (Katy Smith), Bradfield Woods (Steve Hunt), Center Parcs (Graham Hersey-Green), Cavenham Heath (Michael Taylor), Walberswick (Will Russell), Spring Lane (Rob Parker), 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

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

Forest 1&2 (Nick Mason), Arger Fen (Gordon Kennett), Black Heath (Linda Hammond), Nowton Park (Fay Jones), Knettishall Heath (Samantha Gay) and Sizewell Belts (Dayne West). Single-species transects for Purple Hairstreak (Steve Hunt) and Silver-studded Blue (Terry Peake at Blaxhall Common and Helen Saunders at Purdis Heath) all produced useful contributions to the UKwide results. In almost every case, additional volunteers (not named individually) assisted the lead walker. W. Stone, 27 Draymans Way, Ipswich IP3 0QU butterfly@sns.org.uk

Small Copper aberration in Suffolk: 2003–2013 Two further records were added to my list for the Small Copper aberration caeruleopunctata, which is a form with a series of blue spots, normally a maximum of four, along the bottom edge of each hindwing: 25 May 2013 Rushmere Heath TM2044 6 June 2013 Hollesley Heath TM3347 Each was a single specimen. An analysis of my personal butterfly records from 2003 to 2013 reveals 25 of these aberrations recorded out of a total of 598 Small Coppers seen. During this time my wife Anne-Marie and I have closely examined all Small Coppers seen, whenever possible. The percentage of this aberration compared to the total seen is approximately 4∙18. i.e. present in roughly one out of every 25 recorded. An analysis of locations reveals 21 and although I have visited many of these sites on an annual basis I have not found this aberration on the same site in any subsequent years. It would be interesting to see if any other Suffolk recorder has managed to do this. Richard Stewart ‘Valezina’ 112 Westerfield Road Ipswich IP4 2 XW.

Trans. Suffolk Nat. Soc. 50 (2014)

BUTTERFLY REPORT 2013

Annex A. Scarcity for 37 species seen in Suffolk in 2013. Tetrads per Species – 2012 & 2013 (Species listed in order of scarcity in 2013) % of 575 Tetrads

0∙2 0∙9 0∙5 2∙3 4∙0 3∙0 5∙2 4∙2 8∙2 8∙2 10∙6 9∙9 16∙3 0∙2 21∙9 28∙9 27∙5 33∙9 16∙0 36∙5 25∙9 29∙2 25∙2 64∙2 50∙1 51∙0 45∙2 53∙0 55∙8 67∙0 46∙1 58∙1 38∙3 59∙7

Tetrads 2012 None None None 1 5 3 13 23 17 30 24 47 47 61 57 94 1 126 166 158 195 92 210 149 168 145 369 288 293 260 305 321 385 265 334 220 343

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

Tetrads 2013 2 3 3 4 5 7 15 24 25 27 31 51 59 83 84 104 131 131 181 187 194 222 232 236 240 273 290 338 343 363 389 414 451 462 467 476 490

% of 640 Tetrads 0∙3 0∙5 0∙5 0∙6 0∙8 1∙1 2∙3 3∙8 3∙9 4∙2 4∙8 8∙0 9∙2 13∙0 13∙1 16∙3 20∙5 20∙5 28∙2 29∙2 30∙3 34∙7 36∙3 36∙9 37∙5 42∙7 45∙3 52∙8 53∙6 56∙7 60∙8 64∙7 70∙5 72∙2 73∙0 74∙4 76∙6

*cf last

3∙00 0∙88 2∙20 1∙00 0∙95 1∙30 0∙80 1∙14 0∙97 1∙12 1∙22 1∙32 1∙00 #### 0∙93 0∙97 1∙06 0∙89 2∙16 0∙99 1∙42 1∙28 1∙69 0∙70 1∙05 1∙05 1∙25 1∙14 1∙15 1∙05 1∙56 1∙25 1∙94 1∙28

*cf last- Indicates the proportion of last year's cover achieved in the current year∙

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

Annex B. ANALYSIS - 2005 to 2013 Long term trends - for residents and regular visitors. Survey from: to:

2005 2009

2006 2010

2007 2011

2008 2012

2009 2013

Period: Tetrads:Species/Tetrad:

5yrs 994 13.1

5yrs 1003 13.4

5yrs 1003 13.6

5yrs 993 13.8

5yrs 998 14.3

411 292 439 8 118 461 806 799 731 565 119 147 83 402 21 292 505 498 79 720 615 701 714 663 720 115 108 701 805 571 241

405 278 462 7 85 463 820 813 765 618 134 159 79 397 21 297 499 520 78 751 557 689 721 672 738 100 104 725 804 587 252

422 283 475 7 69 450 832 811 765 612 119 178 76 417 20 279 513 500 93 750 537 687 714 694 740 96 104 732 816 634 271

425 280 510 10 166 479 840 833 761 604 109 213 79 440 20 296 556 494 101 738 580 762 760 717 727 81 106 763 824 662 288

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

390 296 412 8 118 442 785 775 718 552 113 128 79 376 22 260 475 504 71 699 604 698 700 635 724 120 104 663 789 528 234

Trans. Suffolk Nat. Soc. 50 (2014)

BUTTERFLY REPORT 2013

Annex B. ANALYSIS – continued Survey

2009

2010

2011

2012 2013

Period: Tetrads:Species/Tetrad:

1yr 645 10∙3

1yr 575 9∙7

1yr 677 8∙7

1yr 575 9

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 27 42 326 353 250 100

148 79 188 4 11 197 380 421 366 311 62 72 26 169 15 121 194 220 32 452 84 276 285 308 363 31 48 323 360 226 118

166 94 168 3 1 149 343 334 260 210 30 61 17 195 13 57 145 158 47 369 92 220 265 305 293 23 48 321 385 288 126

Trend

1yr 640 10∙9 181 104 240 7 131 236 490 467 363 232 27 83 25 194 15 84 273 187 51 290 222 476 462 389 343 24 59 414 451 338 131

Weak but Stable Weak but Stable Gaining Weak Migrant: variable Gaining Stable Stable Stable Stable Weak but Stable Stable Weak but Stable Weak but Stable Weak but Stable Weak but Stable Weak but Stable Weak but Stable Gaining Migrant: variable Migrant: variable Slight recovery Slight recovery Stable Stable Serious Decline Weak but Stable Weak but Stable Slight recovery Slight recovery Weak but Stable

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

Annex C â&#x20AC;&#x201C; Earliest and Latest dates for Suffolk Butterflies (at end of 2013) Recorder

Earliest

Species

Latest

Recorder

Mervyn Bell W. E. Lemmon Stuart Ling R. Havard Stella Wolfe Mike Crewe Terry Hammond Nigel Odin Eileen Coe Mr & Mrs J Forbes Three jointly Reg Etheridge Proctor/ Hickman Ricky Fairhead Anne Welch Colin Hawes Twinch & Barlow Mike Taylor Pete Etheridge Nick Blacker Brian Buffery Four jointly Anthony Cook Two jointly A & E Beaumont Jo Pask Stan Dumican Reg Etheridge Tony Prichard Stuart Gough David Young Jennifer Hadley Rob Macklin Mervyn Crawford Anne Welch Jim Foster

28/5/97 25/4/90 29/5/83 17/5/08 21/5/07 23/3/90 18/3/95 21/2/07 11/3/00 23/4/13 7 Jan 1/4/09 26 Mar 24/4/07 3/6/11 5/5/08 10/6/07 21/6/03 20/6/11 7/6/11 30/6/11 1 Jan 20/2/90 1 Jan 1/1/00 12/3/07 15/1/95 20/3/10 3/6/13 9/4/11 2/6/11 18/3/90 30/5/11 24/4/04 7/4/11 31/7/03

Swallowtail Dingy Skipper Essex Skipper Small Skipper Large Skipper Orange Tip Large White Small White Gn-veined White Clouded Yellow Brimstone Wall Speckled Wood Small Heath Ringlet Meadow Brown Gatekeeper Grayling S-W Fritillary White Admiral Purple Emperor Red Admiral Painted Lady Peacock Sm Tortoiseshell Camberwell Bty Comma Small Copper Purp Hairstreak Gn Hairstreak W-l Hairstreak Holly Blue S-studded Blue Brown Argus Common Blue Chalkhill Blue

28/8/91 4/7/83 12/9/84 25/9/95 18/9/04 21/7/13 25/12/11 19/11/06 5/11/06 21/11/32 27/11/06 30/10/95 16/11/11 10/11/11 08/9/12 8/10/13 6/10/05 1/10/06 26/8/13 11/10/04 26/8/2 31/12/06 20/11/95 31/12/97 28/12/97 14/10/96 12/12/00 16/11/94 8 Sep 20/7/96 28/8/00 13/11/11 30/9/07 27/10/08 611/94 26/8/13

Ian Porter D. Croxson Alan Hubbard Stella Wolfe M. Crawford Ray Hardinge Dave Langlois Stuart Gough Will Brame Mr Richardson Jo Woods Betty Serjeant M. Crawford Reg Etheridge Mel Sheard G. Reeder L. Calvesbert Steve Goddard Steve Hunt Nigel Cuming J. Dowding Nick Dickson Colin Hawes Peter Hobbs Mrs Frost S. & R. Biddle Gawin & Travis R. Stewart Sherman & Hunt R. Havard John Walshe D. Underwood R. Havard Nigel Odin S. Piotrowski Rob Parker

The names and taxonomic order of species follow the new checklist: Agassiz, D., Beavan, S.D. & Heckford, R.J. (2013) A checklist of the Lepidoptera of the British Isles. Royal Entomological Society, St Albans.

Trans. Suffolk Nat. Soc. 50 (2014)

BUTTERFLY REPORT 2013

Annex D-Dingy Skipper Survey, 2013 Overview The Dingy Skipper had an unexpectedly strong season in 2013. It did well across a wide area of the King's Forest, was again found on Thetford Heath and turned up at RAF Barnham and Elveden Center Parcs after absences of seven and six years respectively. Its flight period started late and lasted longer than usual into the flowering period of the bird's-foot trefoil, which was also later than normal. The resulting distribution map shows Dingy Skipper in seven tetrads â&#x20AC;&#x201C; the most since 2004, although this may exaggerate the extent of a single good season. 2013 Survey The pre-arranged searches again turned out to be too early; none were flying on 15 or 16 May, and the earliest sighting was in the archery area on 19 May, and three were seen on 22 May. The main count took place on 26 May, with a team of seven counting a grand total of 83 in a 4 hrs 30 min search. The flight area was found to have extended eastwards, and the Wordwell ride (with nine seen) is showing the benefits of the ride widening work. In the following days, individuals searched the Thetford Heath area, Center Parcs and RAF Barnham with pleasing results. The last sighting was on 16 June. The numbers seen in different areas offer hope that this strong season will have resulted in good breeding opportunities. The sightings around Thetford Heath and Thetford Forest are pleasing, and the reappearances at RAF Barnham and Center Parcs were totally unexpected. The sites visited are listed below, with more detail. RAF Barnham TL8580/8680 The visit to RAF Barnham was made in good weather on 7 June, and early on, one Dingy Skipper was seen in one of its former haunts at the eastern edge of TL8580. Birdâ&#x20AC;&#x2122;s-foot trefoil was present, and the habitat both sides of the tetrad boundary looked promising. Nonetheless, no more were seen during an extensive search of the whole site. The Dingy Skipper is breeding on the adjacent Thetford Heath, so this singleton has at least shown a readiness to re-visit a former stronghold. The gap without sightings has been seven years. Thetford Forest/Thetford Heath TL8480 For the second time, we were able to visit the Thetford Heath nature reserve (staying clear of the stone curlew breeding area). In good weather on 2 June a minimum of seven Dingy Skipper were seen flying vigorously in the north west of the heath (TL846807). The flight area over a bird's-foot trefoil strip extended eastwards towards RAF Barnham, but stopped about 300 m before the boundary fence. A further two were found in the adjacent Thetford Forest re-stock area just north of the St Edmunds Way. On the western boundary of Thetford Heath, two more were seen along the Icknield Way, adjacent to Marmansgrave Wood, where they used to fly until about 2002. This brought the day's count for the Thetford Heath area to a minimum of eleven. It would appear that a healthy colony is now resident in the north of

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

Thetford Heath, and is mobile enough to visit RAF Barnham, the edge of Thetford Forest and along the Icknield Way. This is all an encouraging prospect for future re-colonisation. Center Parcs, Elveden TL810805 This isolated colony existed until 2006 on a small site that has been losing its suitable habitat to a build up of coarse grass. The Center Parcs staff have been checking the site annually ever since – without success, until this year, when they were delighted to see two on 6 June. In King’s Forest (overall) First found 19 May (later than usual). Best count: 83 on 26 May. Latest sighting: 16 June. Extent: From Wordwell to Chalk Lane, and this year extending into four tetrads, all to the east of the B1106. King’s – Chalk Lane area (TL8275 and TL8374) Six were seen in the Chalk Lane area on 27 May. Further along Chalk Lane to the east, five were seen in tetrad TL8474 on 2 June. They were last noted in this tetrad in 2004. King’s – Archery Restricted area TL833737 The best ride of the archery area has been lightly degraded as a result of the extraction of a number of mature beech trees in the northern belt. The count of the archery area on 26 May was just eleven, but another twelve were seen in the adjacent rides, and the focus of the flight area had apparently moved eastwards. King’s – Griffin’s Covert (East of Archery area, TL838735) To the east of the point marked by the corner of forest compartment 204, seven Dingy Skippers were flying in the open patch where they were seen last year, whilst further east 43 more were counted in five bays where the recently planted trees are looking sickly – but the bird's-foot trefoil is flourishing. This marks a significant spread to what is potentially a decent breeding area. King’s – Eastern margin TL841731 A quick check of the easternmost tetrad of the forest found two on 2 June. Singles have been seen here before, but not often. King’s – Wordwell area TL834733 On 26 May, nine Dingy Skippers were flying in the Wordwell ride and one of the bays. It is encouraging that they are using the recently-widened ride, although none were seen in the east-west southern ride this year. King’s – West of B1106 This area was again given a cursory check in 2013, but none were seen.

Trans. Suffolk Nat. Soc. 50 (2014)

BUTTERFLY REPORT 2013

Annex E- Annual Report on Silver-studded Blue for 2013 Season overview The late season of 2013 retarded the appearance of argus again, but the hot dry summer produced good numbers at most sites. The Minsmere count was conducted in two parts. The first, on 5 July was ahead of the peak, and the back-up count on 15 July hit the population peak nicely, and covered some of the minor colonies that often go unvisited. The good flying weather produced high counts, and must have presented excellent breeding opportunities; in all it was an excellent season for the Silver-studded Blue. Results of Annual Count This year, a total of 27 out of 45 sites were counted, and the splendid resulting total figure of 6184 amounts to 113% of our datum for a good year (5470 in 2006). Five sites returned counts of nil, and Walberswick is the one which causes most concern. None have been seen there since 2009, so local extinction is assumed; sadly, we can not explain the loss. The heather encroachment at Minsmere Potbriggs was tackled this year, and we hope to discover some recolonization there in 2014 as the habitat recovers. Regrettably, the Hollesley Common sites were not all completed this year. The results of the 2013 counts are tabulated in the accompanying spreadsheet. Local Extinction at Walberswick NNR Counts at the Walberswick site, close to the New Delights Walks, declined gently from 40 in 2005 to 31 in 2009, but no Silver-studded Blues have been seen there since. This population collapse is worrying, particularly as six count visits have been made over the past two seasons, but they failed to find a single Silver-studded Blue at this National Nature Reserve. The bell heather still looks good, but it now seems certain that the colony has been lost. Sadly the cause of the decline remains unknown. Good News The colony translocated to Blaxhall Common in 2007 has now passed its fiveyear test; it has not simply survived, but shown progressive improvements in transect counts, peak population counts, lengthening of flight period and extension of flight area. An independent survey of the whole common was made by ecologist Neil Ravenscroft; based on transects of 3 separate flight areas, the population was estimated at a total of 900 to 1000. The success was reported to JCCBI (Parker, 2013). The colonies about which concern has been expressed since 2005 include Purdis Heath and Martlesham Heath. Both are the subject of ongoing conservation work, and this seasonâ&#x20AC;&#x2122;s results have been promising.The single-species transect at Purdis Heath has monitored a gentle increase in numbers and a spread of the flight area into the recently restored habitat. At Martlesham Heath the count exceeded 300 for the first time since 2005.

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

Research and Heathland Projects This year, two MSc students undertook academic fieldwork at four Silverstudded Blue sites, and these led to helpful dissertations on egg-laying behaviour (at Martlesham Heath and Lower Hollesley Common) and on habitat management (at Purdis Heath and Ransomes). Preparations were made for next year’s Ipswich Heaths Project, which will involve habitat restoration at 14 heathland sites, many of which are past or present Silverstudded Blue sites. Dunwich Forest Compartment In the Dunwich Forest, the Westleton Heath population has re-colonised a former forest compartment, and this was reported as a positive development in 2011. With a count of 180 this year, it looks as if they have stayed in the new compartment, despite the bracken encroachment. Tabulation – “Results of the 2013 Silver-studded Blue Counts”

2013 COUNTS Location Blackheath Wenhaston Walberswick NNR Dunwich Forest Area 4 Westleton Heath NNR Westleton Common Westleton Football Pch. Minsmere Foraged Sq. Minsmere Reversion Fd. Minsmere Sawmills Minsmere Football fld. Minsmere Natterjack pit Minsmere SW Comp 1 Minsmere Pit Comp2 Minsmere SE Comp 3 Minsmere Comp 20 N Minsmere Comp 20 S Minsmere S Comp3 Minsmere Central C.3 Minsmere Powerlines Minsmere N. Bridleway Minsmere Potbriggs Minsmere N. Grimstones Minsmere E Comp 13 Minsmere C.13 track Minsmere C.13 Tanktrap

Monitored Silver-studded Blue Sites listed geographicallyfrom the North Grid Ref.

Date

Observer

Male

TM420749 TM451727 TM461702 TM4569 TM443687 TM444688 TM459689 TM451689 TM452692 TM451691 TM451693 TM450694 TM457692 TM457691 TM446683 TM445680 TM456693 TM453693 TM461683 TM468687 TM468689 TM462688 TM468681 TM464681 TM466683

27 Jul 05 Jul 11 Jul 15 Jul 08 Jul 08 Jul 09 Jul 05 Jul 05 Jul 05 Jul 05 Jul 15 Jul 09 Jul 09 Jul 11 Jul

R. Havard W. Russell M. Kemp W. Russell D. Rous D. Rous M. Kemp M. Kemp M. Kemp M. Kemp M. Kemp M. Kemp M. Kemp M. Kemp M. Kemp

1 0 124 112 225 21

4 0 56 59 189 7

118 586 108 68 32 531 1285 236

21 189 26 10 3 210 520 63

Trans. Suffolk Nat. Soc. 50 (2014)

Fem

09 Jul M. Kemp 09 Jul M. Kemp 05 Jul M. Kemp

15 Jul M. Kemp 05 Jul M. Kemp

4 352

0 75

Total 5 0 180 171 414 28 ~ 139 775 134 78 35 741 1805 299 ~ ~ 0 ~ 4 427

BUTTERFLY REPORT 2013

Tabulation – “Results of the 2013 Silver-studded Blue Counts” continued 2013 COUNTS Location Minsmere Gravel Pit Comp 26 Aldringham Walks Blaxhall Common Upper Hollesley MOD SCDC Lower Hollesley ‘A’ Lower Hollesley ‘B’ Lower Hollesley ‘C’ LHC Barthorpes small LHC compt 1e Firebreak LHC compt 8c Rushmere Heath Martlesham Heath Parsnip Plantation Ipswich Golf Club Purdis Heath Ransomes CWS Ind. Est. Jacobsen Ind. Est. lagoon fringe Sites counted: With five empty Datum good year: This year as

Monitored Silver-studded Blue Sites listed geographicallyfrom the North Grid Ref.

Date

Observer

Male

TM449669 TM464612 TM377566 TM333472 TM335471 TM342465 TM343461 TM350458 TM349460 TM346462 TM350456 TM338468 TM202448 TM2344 TM327458 TM208432 TM212427 TM207419 TM200410 TM207415

15 Jul 15 Jul 15 Jul 09 Jul 09 Jul 03 Jul 03 Jul

M. Kemp D. Thurlow T.Peake G. Plank G. Plank R. Stewart R. Stewart

1 42 139 15 2 52 272

1 12 21 5 0 2 15

2 54 160 20 2 54 287

01 Jul D. Basham 14 Jul P. Smith

0 ~

0 309

July N. Sherman 06 Jul J. Dowding 07 Jul M. Berry

0 25 15

0 4 3

0 29 18

08 Jul J. Dowding

2013 Totals

4366

1495

6170

2006 Totals % of 2006:

3617

1438

5470 113%

27 of 45

Fem

Total

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

Annex F â&#x20AC;&#x201C; White-letter Hairstreak This butterfly received 36 records in Suffolk and was recorded in 25 tetrads across the county (see 2013 distribution map below for White-letter Hairstreak). It was first seen at Pipers Vale, Ipswich on 1 July and the last record was on 20 August at Aldeburgh and Clare Country Park. The maximum count was of 19 in Dunwich Forest on 18 July. In 2012, it was recorded in 17 tetrads so the records in an additional eight tetrads for 2013 are pleasing. When compared against a longer term (2009â&#x20AC;&#x201C;2013) we see that this species is still relatively stable in the county at 79 tetrads. As with other canopy dwelling species it is always difficult to accurately assess the population and it is a species that requires ongoing study.

White-letter Hairstreak distribution map.

Trans. Suffolk Nat. Soc. 50 (2014)

BUTTERFLY REPORT 2013

Annex G â&#x20AC;&#x201C; White Admiral In 2013, 123 records were received and this wonderful butterfly was seen in 51 tetrads. The first of the year was recorded on 5 July in Hurst Fen, Mildenhall. The last sighting was on 31 August in Bradfield Woods. The Bradfield Woods complex now appears to be one of the strongholds for the species in Suffolk and a maximum count of 57 was also made here on 4 August. The five year period (2009â&#x20AC;&#x201C;2013) reveals that White Admiral has now been recorded in 101 tetrads which relates to 9% of the county. This species has benefitted from an increasing interest in locating new sites for Silver-washed Fritillary. As they both enjoy mature woodland and share similar flight periods it is often possible to see both flying side by side and this perhaps presents one of the true highlights of a butterfly summer. (See 2013 distribution map below for White Admiral).

White Admiral distribution map.

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

Annex H â&#x20AC;&#x201C; Grayling During the year 143 records were received for Grayling and it was recorded in 59 tetrads. The first sighting was in Rendlesham on 2 July and the last on 24 September at Upper Hollesley Common. A maximum count of 60 was recorded at Sutton Common on 21 August. 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 much localised in its favourite Breckland haunts and extremely rare in Mid Suffolk, although it remains widespread in the Sandlings. Overall, its distribution has remained stable since 2000, being found in 9% of the county. This year, several recorders found it in new tetrads within the Sandlings area. A comparison between the east side of Suffolk (TM) and the west side (TL) reveals that both tetrad counts and numbers seen have again dropped off in the west of the county. The map below shows the east/west divide clearly.

Grayling distribution map.

Trans. Suffolk Nat. Soc. 50 (2014)

BUTTERFLY REPORT 2013

Annex I â&#x20AC;&#x201C; Wall A total of 83 records were received during the year and it was recorded in 24 tetrads (See the 2013 distribution map below for Wall). By comparison it was recorded in 23 tetrads in 2012. This is a bivoltine butterfly (producing two broods in a year) and the two distinct generations can be identified from the records received. The early (1st) generation was first seen on 27 May at Bawdsey with the last seen on 29 June at East Lane. A maximum count of seven was made on 18 June at Orford. The late (2nd) generation reappeared first at Hazelwood Marshes on 25 July and then finally at Hollesley Marshes on 6 September. A maximum count of nine was made on 18 August on a walk between East Lane and Shingle Street. As we saw in 2012, the vast majority of records came from the known strongholds of East Lane/Shingle Street, Orford and the Lowestoft/Waveney Valley. The most westerly record in east Suffolk in 2013 was at Sutton Hoo near Woodbridge. There were no accepted records of Wall in the west of the County. What is happening in Suffolk with the Wall is reflected across the rest of the UK in that the butterfly is now becoming a costal species. The Walls position in Suffolk remains critical and all records received in 2014 will be very significant. In order to reinforce this stark situation if we compare the five year period of 1995 to 1999 to the current five year period of 2009â&#x20AC;&#x201C;2013, the Wall has gone from being present in 350 tetrads to only 81.

Wall distribution map.

Trans. Suffolk Nat. Soc. 50 (2014)

Suffolk Natural History, Vol. 50

Annex J â&#x20AC;&#x201C; Small Heath A total of 302 records of Small Heath were received in 2013 and it was recorded in 131 tetrads. The current five year period (2009â&#x20AC;&#x201C;2013) shows it to have been recorded in nearly 300 tetrads, some 27% of the county. The 2013 distribution map below shows the strongholds of this butterfly as the Sandlings in the east of the county and the Brecklands to the west. However, it is also to be found in suitable grassland throughout the county. The first record was received on 11 May at Lackford Lakes and the last one was seen on 28 September at Shingle Street. The maximum count for the year was of 50 recorded on 20 August at the Viridor Landfill site near Lackford.

Small Heath distribution map.

Trans. Suffolk Nat. Soc. 50 (2014)