Clouded Yellow and Brown Hairstreak at Arnside Knott

Clouded Yellow amongst knapweed at Arnside Knott

After a Butterfly Conservation marathon I reflect on all that has been discovered, and achieved. On Members Day we filled a lecture room at Leighton Moss for a morning of presentations, followed by an afternoon field-trip on Arnside Knott.
Moth-traps were opened and amongst those exquisite and tiny was a large Poplar Hawk Moth, a resident nocturnal moth that, once released, spent the morning roosting on a shady buddleia leaf.  A tiny Humming Bird Hawk Moth nectared on the shrub's  flowers, never still, and with rapid wing beats a video works best.  All true butterflies feed but the Poplar Hawk Moth  does not.  Like several species of moth it cannot feed but lives off reserves of fat. 

At Arnside Knott a female Silver Washed Fritillary swooped about fallen tree-trunks encrusted with peeling bark, laying  eggs in crevices.   'She almost landed on your camera,' our leader Chris told me. The butterfly alighted  below the log we leaned upon so we peered over it into shadows. So close, and so elusive.  She must have been aware of our presence but did not perceive us as a threat. Chris pointed out that there were plenty of violets, the food plant of her caterpillars. Interpreting  behaviour as we witness it makes a scene memorable.
A Purple Hairstreak is a life tick, for me. This arboreal butterfly flitted about oak and alighted on hazel.
 I've often seen Northern Brown Argus, Scotch Argus and Grayling. But when Dr Jules SImons mentioned that she'd seen Clouded Yellow here yesterday I fervently hoped she could conjure them into being. Clouded Yellow is a 'true migratory butterfly' which we saw throughout Easter 2024 in Tuscany.  On one long, leisurely interlude we sat amongst periwinkle flowers,  seeing a play of sunlight and shadow create  translucence and shades of colour through Clouded Yellow wings.  One butterfly hangs from a blue periwinkle flower,  green as the surrounding leaves. 

With a spirit of co-operation and sharing in a large group of keen-eyed experts we see so much more. But to take photographs I like the freedom of being alone.  Strong sunlight blazed colour from those first Clouded Yellow  down in the herb layer where splashes of yellow could be  flowers or fading vegetation. Like someone who completes a marathon, I'm delighted but could  do better. In my mind's-eye I can still see sharp images, with rich colour through translucent wings- like the sudden illumination of stained-glass windows. Colour alters significantly, depending on the incidence of sunlight.  And here are my first British Clouded Yellows. 
​There's intense focus from our experts when they came upon a morph of Clouded Yellow, Helice variant which is rather paler.  There's infinite variety in colour so I pass on that one. Released, it settled on a lady's T shirt. 

It was almost 5.00pm, the hottest time of the day and an uphill slog but we were approaching the stand of hemp agrimony where we'd often found Brown Hairstreak, a striking arboreal butterfly.   Our subject was settled on a flower so this was a more leisurely photo-shoot.

Painted Ladies are doing well in this hot, hot summer. Chris pointed out that some are rather smaller.  When a butterfly emerges from a chrysalis  that's its adult size, it does not grow further.  When caterpillar or chrysalis has been under stress, through heat or drought, the emerging butterfly can be smaller, or damaged. 
Thanks to Chris Winnick and to all at Butterfly Conservation's Members Day for a tour de force, a memorable day when the weather was perfect and Arnside Knott did us proud.  
A day like yesterday whets the appetite for more, brings more questions. The Clouded Yellow is a migratory butterfly and cannot overwinter in the UK as it's too cold. But on 12 August the fifth heat-wave of the year will be upon us. 28 degrees forecast.  So how is the species adapting with climate change? There are already records of a few overwintering in favoured spots on the Dorset cliffs. In the meantime, where is its reproductive base, the location where the species breeds in numbers and overwinters. Clouded Yellow comes from North Africa and southern Europe.  We saw numbers in Tuscany in 2024. Does it overwinter there? Below, a sequence of Clouded Yellow feeding on periwinkle and rosemary on 3 April 2024.