Last year reinforced my belief that there is no such thing as a truly bad butterfly summer, though it tried hard. Butterfly Conservation’s Wider Countryside Survey found the year was good for some species, especially those whose larvae feed on grasses. Meadow Browns, they say, had a good season, and also Ringlet.
Some 17 British butterfly species breed on various grasses, from the Browns and Skippers families. A few of these like cool wet summers (notably Meadow Brown and Ringlet), some like hot dry summers and so had a difficult time last year (Silver-spotted Skipper, Small Heath and Wall Brown), and a few hate drought (Speckled Wood and Ringlet again). So they are a mixed bunch.
Personally, I found Meadow Browns to be very patchy last year – in some places they abounded, whilst elsewhere they were scarce, especially in woods. Ringlets also seemed poor in woods. But one of the key points about poor summers is that some butterflies do well in them, at least locally. We are far from sure why, for butterflies are complex creatures impacted upon by numerous factors. Much depends on where the sun shines and which places escape the worst of the deluges.
Some butterflies seem to do well when their larval foodplants grow lush – notably, Chalkhill Blue, Dark-green Fritillary and some of the grass-feeding species. This seems to be the group that did best last year, when vegetation really did grow well. It may also be that larval parasites and/or invertebrate predators fare poorly in wet summers, which may help explain why Peacocks appeared in good numbers in some districts during August – or maybe they like tall nettle growth.
Looking forward, our butterflies have had to cope with a run of poor summers since 2006 and really do need a decent summer this year. So do we.
Matthew Oates celebrates his 50th season of butterflying this year, is a naturalist working at the National Trust and can be followed on twitter at @NTMatthewOates