Yesterday I learned that in the last five days, while Oxonbirders have been beating our annual path to the Chiltern Escarpment to observe migrating Ring Ouzel, the little jewels that are Green Hairstreak have emerged nearby almost unnoticed. Mid-April represents a fairly early start to one of my favourite butterfly’s flight season. This is always a special moment in my wildlife calendar and with their appearance my heart is gladdened.
In presenting my British butterfly year on this blog I will divide species into local and scarcer categories. Generally speaking “local” denotes anything that may commonly be seen in town gardens, while the “scarcer” ones are those that require particular sites or habitats to be visited. Each of the latter category will be reported under the same heading style as this post.
Green Hairstreak is usually the first scarcer species to appear, and a good place to see them at Aston Rowant NNR (SU730967) is along a brambly bottom edge of the chalk hillside just above the Sunken Way trail from the car park (see site plan above). A lot of this habitat had been newly cut but upon reaching an uncut portion lower down the slope I quickly saw a first butterfly. As I reached for my macro lens this individual flew back into cover and then there was a bit of a wait for another one to appear.
At this point sunlight was reduced by light cloud, but as soon as proper sunshine broke out the butterfly (below) emerged from cover to sit up and pose perfectly. What a delicate and understated little beauty, I just love ’em! I saw seven Green Hairstreak in all at this location, then walked around the reserve to prospect for more.
If traffic noise is disregarded, from the M40 motorway that dissects the site, Aston Rowant NNR is a beautiful chalk hillside reserve. It is worth visiting just to experience the spectacular summer wildflowers that support an abundance of insect life including Dark Green Fritillary, Adonis Blue, Chalkhill Blue and Silver-spotted Skipper butterflies. I regard this place as my “home ground” and have spent many a contented hour here.
After the lower location I tried another spot just over the crown of Beacon Hill that had been described to me as supporting Green Hairstreak, but could not find any. Whilst taking a nature break there a bi-plane flew low and right over my head, proof not only that privacy can rarely be relied upon but that the tranquillity of no nature reserve (for those who seek it) is safe from the invasive species Plonkerus maximus.
Lastly I drove round to Linkey Down, just south of the M40 and the area where the Ring Ouzel are found. Seven were said to be present today but I saw just two of them in company with Wayne Bull. Other birders came and went but I was more concerned with butterflies today. The Green Hairstreak habitat here has been cut severely by English Nature in the last two years, and on encountering a working party recently I took the opportunity to enquire why. The explanation was that in managing a patchwork habitat EN must prioritise what should stay or go, and invasive Hawthorn had been removed here. No doubt there are sound habitat management reasons for this but I still regret the loss of what was a Green Hairstreak hotspot. I found none today though conditions became lightly overcast while I was there.
So what of “local” butterflies in the first half of April? Brimstone have been flying everywhere this sunny week, and Orange Tip are beginning to appear too. Of the hibernators, Peacock Butterfly and Small Tortoiseshell are plentiful and I recorded my first two Comma on a visit to the South Oxon Downs yesterday. In that location I also saw my year’s first Orange Tip and Small White, having seen a first Speckled Wood a week ago at Standlake Common.