United Kingdom Butterfly Monitoring Scheme annual report 2009

HIGHLIGHTS • A major milestone was made as the number of sites monitored in 2009 exceeded a thousand, whilst trends were assessed for 53 of the 59 regularly occurring UK species. • Following two of the poorest years on record for butterflies in the UK, most species made some recovery in what turned out to be a mixed year, still ranking below average (23) in the 34- year series. • The year ranked as the second best on record for Painted Lady migration with a huge influx in May/June. • Many expanding species continued to do well, whilst five species produced their highest index of the series – Comma, Green-veined White, Ringlet, Speckled Wood and the habitat specialist, Large Heath. • However, despite a warm, sunny start to the year, much of the butterfly season in July and August was once again characterised by wet weather having an adverse effect on a number of species. • Four species had their worst year with continued declines for some of our most threatened species – Duke of Burgundy, Heath Fritillary, Lulworth Skipper and Wood White. • Other threatened species, as well as some of our commoner species, still produced low indices despite the slight recovery from 2008. • For 47 of the 53 species assessed (89%), the mean flight date was advanced compared with the series average, and for the majority of species which fared better than in 2008, the mean flight date was advanced by 1-2 weeks.