Green Hairstreaks on Otley Chevin enduring a Storm

PICTURES FROM THE GLOOM!

Green Hairstreaks seeking escape from an impending storm on the Chevin, West Yorks, May 26th 2000.


Gloom       Gloom     Gloom


(Storms on the Chevin tend to be dramatic in any case. One need only recall that the painter, W M Turner used a sketch of one as  backdrop to 'Hannibal crossing the  Alps'.)  Green Hairstreak Punctata hiding from the storm..............

Above photographs show the the storm about to break............
 
Pages from a notebook accompanying the photographs....


26th May 2000. Otley Chevin: 'A thoroughly miserable day'. BBC Weather View. 'The worst storm to hit the Netherlands in decades passed across northern England yesterday' The Guardian, 27/5/2000.

      It was the best of days it was the worst of days. It began quite sunny, then clouded over, followed by fine drizzle, then a downpour. It remained cloudy all the time. I had walked up the Chevin. Believing it to be hopeless I decided to check out the bilberry just in case.

      The leaves did not have the rust spotting I had half expected and weren't all that different from the bilberry plants at Shibden Head - with one exception the leaves were more reddish because the field was as thickly carpeted as Shibden Head (between Bradford and Halifax)  and the areas of thinner younger pinkish green bilberry shoots more noticeable. About to turn around and go back I suddenly noticed a pair of Green Hairstreaks (male and female). At no time the sun ever come out but it did feel quite mild: the T & A put the maximum temperature at 57 degrees and the wind was very definitely from the south west. Neither of the two butterflies were very active and one settles immediately, with the other settling close by though I was shortly to lose sight of it altogether as I decided to concentrate on the former.

       For the next 3 to 4 hours I closely observed the first Green Hairstreak as I sat down right next to the butterfly while the storm raged all around us. It never once strayed from the plant nor sought shelter from the rain at any time even though an actual downpour developed lasting well over an hour. During this time rain drops would frequently strike the butterfly and in response it would flex itself. But at no point did it seek to hide deep within the bilberry, remaining close to the top of the bilberry shoot. Sometimes its antennae would move and sometimes its front legs, as if it felt it needed to move. During the heaviest part of the downpour, raindrops would strike the butterfly with such force as to almost dislodge it. But it would then valiantly crawl back up the stem some 5 to 10mm. Having observed the Hairstreak for some three hours I formed the impression it looked rather more dishevelled than before the storm.

      Also it appeared to swing its undersides  around in the direction of the sun even though it remained hidden from view. Maybe, like the Honey Bee, it is sensitive to polarised light? Only when the downpour was at its height did it appear to angle its wings to the direction of pouring rain so its wings were edge on to the slant of the downpour. Initially when I disturbed it, before the rain started to fall, the butterfly would crawl and swing from one leaf to the next. There was an absence of that tumbling motion evident in both day and night flying moths when, once disturbed, they twist and fall into the undergrowth.

      Do the butterflies behave in a similar fashion on damp overcast days when a keen north easterly is blowing? Is it perhaps the direction of the wind that is the all important factor''

      I have never before observed an insect so closely. Sitting out there drenched to the skin, trousers soaked, hands growing red with the cold, I thought few at my age (late 50s) would ever do this. Close observation was rescuing me from myself. I became absorbed in my object. Had anyone observed this phenomenon before I did. All I needed was for the sun to come out to see what it would do next. This endurance test was in the nature of a triumph.

Stuart Wise


Gloom Green Hairstreak Gloom


The problem with these photographs of Green Hairstreaks in the gloom is that they all fail to bring out the extremely threatening and very dark sky which merely appears as an unconvincing white backdrop. This is in stark contrast to some photos of Marble Whites at Brockadale, West Yorks elsewhere on this web.
 

Below:  Four photos showing a beetle approaching a comatose Green Hairstreak during the lashing rain. The beetle is probably unable to distinguish butterfly from bilberry leaf as it was also extremely difficult for the human eye to do so.

Insect Insect
Insect Insect

  

28th May 2000. Otley Chevin (See sequence of photos below text)

       Day began overcast with a sharp, north-easterly wind and though not so dark overhead as on Friday it was chillier.  There were no Green Hairstreaks to be seen when we arrived on the Chevin. After an hour we found them on the lower portion of the big field close to the wall. We saw three practically instantaneously lying on their sides basking in the sunshine. Almost immediately there was a shower of rain. A Green Hairstreak I was observing dropped deeper into the bilberry-a rather different form of behaviour from I had observed on the previous Friday. I kept it under observation for an hour. At the height of the shower the butterfly realigned its wing so its upper wing margins were edge on to the shower. Yet it received a good drenching and in fact every Green Hairstreak looked a bit dished, even the mating couple - a punctata and typical form - did not look in a pristine condition (the female could only have emerged that morning). The later stayed mating for at least one and a half hours unlike the 20/25 minutes we timed merely a few days earlier on Banstead Downs, south London.

     Gloom     Gloom

    Fig 1. sunlight above bush                     Fig 2. Butterfly about to descend            Fig 3. Moving deeper down

      Gloom    Gloom

     Fig 4. Last of the sunlight                         Fig 5. Camouflage among leaves           Fig 6. Ah! A punctata

 

  Gloom      Gloom

       Fig  7. Almost invisible                             Fig 8. Head on. Invisible!