Saturday 20 July 2019

Silver washed Fritillarys at Bernwood 18th July 2019

By way of a change to my familar routine I visited Bernwood Forest in the late afternoon today rather than the morning, taking advantage of some welcome late in the day sunshine, as the grey cloud relented and parted to reveal blue sky. To be honest the major attraction of this location in June and July, for both me and many others is the presence of Purple Emperors but today I was more interested in the Silver washed Fritillarys that patrol the woodland rides and feed on the bramble flowers that grow in profusion in the more open areas of the forest.

Silver washed Fritillary-male

Silver washed Fritillary-female
Silver washed Fritillarys at Bernwood tend to be taken for granted as everyone is looking for the much more enigmatic, elusive and cantankerous Purple Emperors, whose sporadic appearances high above the trees or occasionally on the ground are completely unpredictable and totally alluring to butterfly obsessives. In direct contrast it is virtually impossible to ignore the equally large Silver washed Fritillarys as they power along in rapid flight or settle on a bramble flower, their ginger orange colouring shining bright against the greenery of the trees and bushes.

Thankfully Silver washed Fritillarys can be thought of as almost common here and for once are a butterfly that can be looked at without feeling anxious concern about its welfare which is a pleasant situation to report, as so many of our native butterflies are now in alarming decline.

This butterfly is big, one of Britain's largest and hardly hides its light under a bushel. Regularly they come hurtling along at speed down the rides, switchbacking up, through and under the mature trees but always returning to the sunlight. The males are a very bright orange, an intense deep biscuit orange, liberally marked with variable black markings. Females are a duller brownish orange and look a shade darker. The underwings of both sexes and from which the butterfly derives its name are suffused with pale green and broad bands of silver. 

It is the males that are usually the most obvious to onlookers such as myself as they endlessly swoop and glide at speed, forever on a quest for females. Their non stop, action packed existence is the epitomy of a butterfly's short life as their modus operandi is one of almost constant movement in rapid flight, exuding a sense of urgency, giving emphasis to the fact that life will be over very quickly for them and the process of procreation for next year's brood needs to be achieved as soon as possible.

This knowledge brings a gentle melancholy to me as I watch them and realise that soon the butterflies will be gone from this year and like them I only have a comparatively restricted time available to see this much loved group of insects, so familiar since my early childhood. Time is even more of the essence, when one considers that the butterflies only become obvious in sun and warmth, those two forever fickle constituents  of our weather.

Slowly the afternoon  slipped imperceptibly into early evening and the wood became quiet and deserted by most, and I found myself alone, standing on a broad track of summer grasses bordered on both sides by verges harbouring a variety of wild flowers, then beyond, grassy ditches and clumps of low growing bramble. I stood facing one such bramble that was still in flower, although many are now going over, the flowers already commencing to drop petals and soon to become hard, green, spheres that will swell and ripen into a shiny blackness by autumn.

Silver washed Fritillarys were amasssing on what suitable flowers remained on the bramble, four, five, six even were in close proximity, constrained by the comparative lack of flowers.They were  mainly females, feeding frantically to store energy for the coming night. Two or three clustered on one favoured head of flowers, smothering the small cluster with their wings and forming a living spike of butterflies rather than of flowers.

The two or three females were never really still but moved about the flower spike minutely examining every inch of the flowers Their outstretched wings moved slowly up and down, flexing gently, rhythmically, as if they were conveying a quiet satisfaction and contentment at the nectar they were imbibing. Occasionally wandering males floated out of the shaded wood and planed down on outspread bright ginger wings to feed with but not trouble the females. Most of the males are now showing signs of wear, with variable tears in their wings or frayed edges and one even had hardly any wing left on one side, giving it a lopsided look, but it could still fly perfectly adequately despite this handicap.

Other fritillarys, male and female, struggling to find a suitable bramble flower, tried nectaring on nearby flowers such as Meadow Sweet or Marsh Thistle but it was obvious the taste of these was not to their liking and after a few desultory probes  they would fly back to the bramble.

I delayed my departure along the track as I was curious to see where the fritillarys would go to roost once they ceased feeding. I really had no idea how this butterfly behaved at the close of the day and was intrigued to know if they would remain low down in the vegetation or go up higher into the surrounding larger trees to roost.

I stood patiently and waited as the wood and its butterfly residents slowly began to cease activity. It was now approaching seven in the evening and most other butterflies had disappeared or were perched, dormant on grass stems and flower heads.

Small Skippers

Marbled White
Shortly after seven thirty the last two remaining fritillarys flew up from the bramble, rising to about twenty feet to settle on spread and flattened wings for one last time on the leaves of a silver birch above the bramble. Would they roost there? Surely not as it looked far too conspicuous a perch and anyway their wings were spread wide, whereas roosting butterflies close their wings and sheath their upper wings inside the lower wings to minimise their profile.

The two fritillarys remained prostrate on their respective perches, some way apart, on either side of the birch, their wings pressed and flattened on the shiny leaves of the birch. It is quite a distinctive behaviour and once seen is not forgotten. Last year I recall watching the smaller Pearl bordered Fritillary perform this action on a late spring evening at a wood in Sussex. Neil Hume was with us then, a nationally renowned butterfly expert and he described it as 'pancaking.'

Then as if from some unknown, unrecognised signal, both butterflies flew together over my head and across the track, gaining height to vanish into the dark green leafy security of an old oak, presumably to roost.

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