Wet Sleddale and Butterfly Conservation

Tussocks of Cotton grass down toward Sleddale Beck

As house martin swoop low over drifts of pignut by Wet Sleddale reservoir I wonder what the day may bring.
There was a heat-wave over May Bank Holiday, then unsettled weather. After overnight rain the morning is chilly,  only a hint of blue and rain never far off.   The rare Marsh Fritillary and Small Pearl Bordered Fritillary are the target species on this Butterfly Conservation field-trip.   On such a morning they'll be roosting amongst  tussocks of grass and sedge where water-tracks drain off Shap Fell down to the reservoir.   We're wearing sunglasses, woolly hats, waterproofs and wellingtons for yomping through water-logged tussocks and ground poached by Belted Galloways and Belgian Blues whose conservation grazing creates  habitat vital for these  butterflies.   Martin had been here on a recce the previous week and he and Chris are keen-eyed and expert.  By the end of the outing Chris has a tally  of 70 Marsh Fritillary and 6 Pearl Bordered Fritillary.  A count of 70 and probably many more, says Chris.  So this year the Marsh Fritillary, is doing well.  Less good news for the Small Pearl Bordered Fritillary.

On such a morning you might pass this way unaware of these beautiful and precious butterflies because they're not flying.   But the rain holds-off. and by early afternoon the sun breaks through cloud and the temperature rises to 17 degrees.  Earlier, we'd found solitary butterflies roosting. On our return in the afternoon  we  watch numerous Marsh fritillary flying low over vegetation close to the water's edge.  Females can lay a large clump of eggs on the underside of a leaf of Devil's bit scabious almost within the hour of mating.  So a warm and bright afternoon gives them a chance. 
Next day sees unremitting rain.   So how will these two key Fritillary species fare? It's challenging weather, low temperatures, blustery winds and heavy showers. In such conditions Fritillary cannot fly, cannot feed or breed.  All they can do is roost down in a tangle of tussocks, scant shelter through downpours. 
I came here in quest of Marsh and Small Pearl Bordered Fritillary on 28th  May 2024,  knowing this was their peak-flight time but unsure where they'd be .   After a spring drought, through April, flora was stressed but there had been recent rain so the track was puddled.  No butterfly experts with us that day,  so we were fortunate to find  Marsh Fritillary settling on the track and close by, their  upper-wings displaying bold pattern and colour.
This morning, Marsh Fritillary roost torpid amongst tussocks.  Hidden in a weave of grass-stems, they're hard to spot but Martin and Chris find them.  Their underwings are exquisite,  with soft and subtle patterns in a dissolving, water-colour wash of warm tints.  Antennae are tipped with gold that runs toward the head. Gold banded with black. And golden legs with a minute  hook at the tip of the feet (tarsi) to clutch a blade of grass.   One of my images shows the tarsal claw, a microscopic hook. Butterflies use this to clutch, to climb vegetation, and it has sensory hairs to taste a plant.  
From the packhorse bridge over Sleddale Beck Martin spies a Beautiful demoiselle swooping for insects over  roaring water, then alighting on a leafy branch.  Excited voices when we first glimpse this beauty.  Each time the demoiselle returns to the same perch and we attune to the pattern of its behaviour.
 In May 2024 I photographed a male Beautiful demoiselle above Kentmere Tarn, dark wings concealing much of its body.   Today's demoiselle is a wand of brilliant blue  with  only a hint of wings visible at the tip of its abdomen.  
Martin's dragonfly book  suggests that 'immature demoiselle have fainter wings.'  But that they only feed over a beck once they're mature so this is something of a puzzle.  The fun of a field-trip is discovery, and to come away with puzzles not entirely resolved, and with more questions.  I wonder ----
 I reflect on visits here  in late May and early  June 2025 
Wetsleddale, in quest of Marsh Fritillary

t Sleddale with Small Pearl Bordered Fritillary and ...
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Pignut for chimney sweeper moths,  Marsh violet for Small Pearl Bordered Fritillary, and Devil's-bit scabious for Marsh Fritillary.  Three important food plants for their caterpillars.
In a sweeping drift of flowering pignut Martin finds a chimney sweeper moth to show us. 
​ Pam seeks, and finds, the rare Spignel, or Baldmoney, Meum athamanticum,  a strongly aromatic plant new to many of us.
Beside the water-tracks descending toward the reservoir there's sphagnum moss, sundew, butterwort, marsh lousewort and heath-spotted orchid.   And a lovely patch of Bird's-eye primrose,  Primula farinosa.  
I love the flora of blanket bog, heath and mire.  The ruby-red of sundew glistens amongst the delicate blue flowers of butterwort.  There are green spears of bog asphodel, its starry yellow flowers soon to be a summer highlight. 
Return in late summer and on Devil's-bit scabious there will be silken webs spun by Marsh Fritillary caterpillars to protect them from predation.   A web-count will give a good idea of how successful 2025 has been for the Marsh Fritillay.

Wetsleddale and Hobgrumble Gill
​On 5th September2013  I walked this way by Sleddale Hall and up onto the fells. (see link above) A wider geographical and natural history context and a different perspective on Wet Sleddale. 
Thanks to Chris WInnick and Martin Chadwick who led today's excellent field-trip for Butterfly Conservation.