Surrey & SW London Branch of Butterfly Conservation Butterfly and Moth Report 2018 Contents: Weather report, Regional Conservation Strategy, Butterfly report, Moth report, Transect report and WIder Countryside Butterfly Survey, Small Blue project, Oaken Wood Reserve, Silver-spotted Skipper, Hairstreaks, SW London’s butterflies. Surrey & SW London Branch of Butterfly Conservation - Butterfly and Moth Report 2018 Contents Introduction Simon Saville Page 3 Weather report 2018 Harry Clarke Page 3 Regional Conservation Strategy Steve Wheatley Page 5 Butterfly report Harry Clarke Page 6 Moth report Paul Wheeler Page 13 Transect report Bill Downey Page 24 WIder Countryside Butterfly Survey Bill Downey Page 26 Small Blue project - spring 2019 Fiona Haynes Page 26 Oaken Wood Reserve Harry Clarke Page 28 Silver-spotted Skipper Harry Clarke Page 29 Hairstreaks Bill Downey Page 30 SW London’s butterflies Simon Saville Page 31 Area covered by the Surrey & SW London Branch The Branch area covers Vice-County 17, the borders of Surrey as they were in 1852 when the vice-counties were introduced for biological recording. Broadly, VC17 comprises the modern county of Surrey plus: ● Inner London boroughs - Wandsworth, Lambeth and Southwark ● Outer London Boroughs - Kingston, Merton, Richmond, Sutton and Croydon ● The area around Gatwick Airport Spelthorne District (north of the Thames) is in Surrey, but is outside VC17. Definitions ● Occupancy - a statistical measure of the distribution of a species, using the probability of detecting the species within a given monad (1km x 1km square). Records from all sources are used. ● Abundance - a statistical measure that enables a population size to be compared year-by-year, using UK Butterfly Monitoring Scheme transect data where a site has been monitored for at least four years. ● Total number of butterflies - the number of individual butterflies recorded, from all sources. ● Total number of records - the number of records, each of which may be of one butterfly or many. About Butterfly Conservation Butterfly Conservation is the UK charity dedicated to saving butterflies and moths, which are key indicators of the health of our environment. We improve landscapes for butterflies and moths, creating a better environment for us all. Join at www.butterfly-conservation.org. The Surrey & SW London Branch of Butterfly Conservation monitors butterflies and moths and carries out practical conservation work to improve habitats. Join us on one of our field trips to the best wildlife sites in the area. See www.butterfly-conservation.org/surrey or email [email protected]. Butterfly Conservation is a company limited by guarantee, registered in England (2206468). Registered Office: Manor Yard, East Lulworth, Wareham, Dorset, BH20 5QP. Charity registered in England & Wales (254937) and in Scotland (SCO39268). Cover photo : Jersey Tiger, © Bob Eade. This moth used to be scarce and a suspected immigrant. Since being found in Forest Hill (London) in 2004, it has become common across most of SW London. 2 Butterfly Conservation - Surrey & SW London, Butterfly and Moth Report 2018 Introduction Simon Saville, Branch Chair 2018 was an odd year, weather-wise. The winter Blue project. You can read about these activities was mild, then we had a very cold spring, followed later in this Report. by a hot any dry summer. As a result, the season started late. Those species on the wing in May - We continued to increase our focus on London, in July fared well, but later species suffered. preparation for the Big City Butterflies project, which started in Feb 2019. I have included a short Transect data showed that Brown Argus and item on London’s butterflies in this Report, showing Speckled Wood thrived, recording their third best that the capital is surprisingly good for wildlife, year on record. Common white butterflies also even in central areas. experienced a good year after a recent run of below-average seasons with Large White Once again, I would like to put on record my abundance up 118%, Small White up by 155% and thanks to the large number of people who have Green-veined White up by 63%, again due to warm contributed to monitoring and conservation work and sunny weather from April to tJuly. over the past year. The hot spring and summer was not ideal for all Thanks are also due to the many landowners and species. Some grassland butterflies struggled, not partner organisations that have been so helpful - helped by drought conditions drying out caterpillar especially the National Trust, Surrey Wildlife Trust food plants and reducing nectar flow. and London Wildlife Trust. Without all this effort and support, this Report would not be possible. Gatekeeper numbers dropped by 20% from 2017 levels and the Small Skipper and Essex Skipper Finally, my thanks to all those who co-authored were down by 24% and 32%. It was also a poor this Report, which is an important record of the year for some garden favourites in Surrey. The work done in 2018. This Report is available on our Small Tortoiseshell slumped by 38% and the website www.butterfly-conservation.org/surrey. As Peacock was down 25%, while the migratory Red last year, hard copies have been made available to Admiral crashed by 75% after a good 2017. volunteers, transect recorders and key partners. Volunteers continued habitat management If you have any comments, please send them to at the Oaken Wood Reserve (for the Wood White) [email protected]. and along the North Downs as part of the Small Weather report 2018 Harry Clarke The diagrams below show the climate data at The average figures for each month (solid lines) Heathrow Airport as provided by the Met Office. are calculated for the years 1981 to 2010, which is Heathrow Airport data is used, as the data is a standard used by the Met Office. The 2018 readily available from the Met Office website, and values shown as dashed lines. it is the closest weather station to Surrey. The winter of 2017/18 started off with a wet The plots show for each month: December and January with temperatures slightly ● Mean daily maximum temperature above normal. That was followed by a cold ● Mean daily minimum temperature February, with air frosts noticeable. ● Air Frosts (number of days) ● Total rainfall (rain) Overall the mean winter temperature was as ● Total sunshine duration (sun) average, and slightly wetter in the London area. The “Beast from the East” provided very cold weather in late Feb - early March. 3 Butterfly Conservation - Surrey & SW London, Butterfly and Moth Report 2018 Spring started off in March being cold and wet. This caused stress to many plants, most Temperatures did not rise above the average until noticeable on the heathlands with brown patches mid-April, resulting in a later Spring than we have from the Ling Calluna vulgaris dying off, while the become accustomed to. Temperatures continued drought resistant Bell Heather Erica cinerea rising in May which had above average sunshine. remained in flower. The Summer of 2018 will be remembered for the Autumn saw temperatures return to normal, with long hot dry spell, with many areas experiencing no September being drier and sunnier than normal and rain for three months, with rain only returning to typical weather during October. Surrey in August. Heathrow Airport temperature and air frosts - 2018 Heathrow Airport rainfall and sunshine - 2018 4 Butterfly Conservation - Surrey & SW London, Butterfly and Moth Report 2018 Conservation strategy update Steve Wheatley, Regional Conservation Manager We are three years into the delivery of our new 10 moth. (This work also recorded another Surrey year Action Plan for SE England and I’m pleased priority – the Common Fan-foot, which despite its to report that work is underway for nearly all of our name, is now incredibly rare). highest priority butterflies and moths. We identified new target areas and are continuing Wood White the survey work this summer, working closely with We’ve been working closely with the Forestry the National Trust, Crown Estate and other Commission ensure the maintenance and partners. enhancement of Wood White habitat around the Chiddingfold complex. In addition to boosting the Silvery Arches (moth) Wood White population, this will help other high Searches are being undertaken this season to look priorities, like the Drab Looper moth. for the caterpillar. If successful we will be able to roll out a survey programme to land-managers and To complement this, volunteers at Oaken Wood our conservation partners to search. This will give are working hard to enhance the habitat there (see us a much better understanding of this rare moth’s page 28), and this is also helping one of our other distribution and will inspire land-managers to Regional priorities, the Betony Case-bearer moth protect more of the habitat. (found nowhere else in the UK). Agonopterix capreolella - Paul Wheeler has been Butterfly Conservation has just been awarded a investigating this micro-moth that feeds on Burnet grant from the National Lottery Heritage Fund to saxifrage at Pewley Down. launch a project for an extensive programme to extend and enhance habitats even further. This Straw Belle is being monitored by Gail Jeffcoate project will begin in 2019. and others at Box Hill. It would be great to encourage this moth back onto other surrounding Silver-studded Blue and Grayling sites. Harry Clarke has been busy assessing heathland habitats and speaking with heathland managers The two high priority species for which we have not about potential work. Silver-studded Blue yet made significant progress since launching this champions in neighbouring Berkshire and Conservation Strategy are Phyllonorycter Hampshire have also been busy, doing similar work scabiosella , a micro-moth that feeds on Small that will link up with the Surrey populations. We’ve Scabious, and the Shoulder-striped Clover which also been liaising with the MoD who own and might be found on some of the large closed MoD manage some of the most extensive areas of our sites in Surrey.