Friday, 29 June 2018

Heatwave ...

Purple Emperor (Apatura iris)



2018 is turning out to be an excellent year for the Purple Emperor in my local woodlands. My first official sighting this season came on Tuesday, 17th June, with several sightings in the traditional areas of Chiddingfold Forest. Numbers have been steadily building and on Monday, 25th June 2018, I counted at least 25 separate males and had multiple sightings of many individuals. It has also been a good year for iris aberrations with at least three ab. afflicta (Cabeau, 1910) being observed to date; the first found by Jan Wilczur on the 25th June.

The current heatwave has meant that the best time to see grounded males is early morning; the earlier the better. By early-mid-morning, when all remnants of any early moisture have evaporated, the males have been observed flying low over the woodland tracks and, when not searching the sallows for females, nearly always alighting in areas of shade where they actively try to extract minerals from the parched ground. Both sexes can also be found feeding from sap runs though these can be difficult to locate. By midday, both sexes, probably due to the extreme temperatures, have been resorting to their arboreal home where they bask in the shade - I can’t say I blame them.

More at:

Wednesday, 6 June 2018

Spirit of the oakwood …

Small Pearl-bordered Fritillary (Boloria selene)



A visit to the Ardnamurchan peninsula at any time of year is always a great pleasure but in early June it becomes a very special place. Ariundle National Nature Reserve near Strontian is one of the many jewels in the stunning Scottish landscape and it is here, observing gems such as the Small Pearl-bordered Fritillary Boloria selene, that one can truly feel at peace with nature. Time your visit well and patrolling males can be seen flying a short distance from the ground, alternating a burst of rapid wing beats with a short glide, searching out freshly-emerged females hidden amongst the vegetation surrounding the beautiful Strontian River.

The strongholds of B. selene are located throughout much of Scotland and Wales, and in the north-western and south-western counties of England with scattered colonies elsewhere. It is absent from the Outer Hebrides, Orkney, Shetland, Ireland, the Isle of Man and the Channel Islands. The adult insect first emerges in south-west England, where it may be seen from the beginning of May. It emerges in the second half of May in other parts of England and generally does not make an appearance in Scotland until early June. The early emergence of the species in south-west England often gives rise to a partial second brood, which appears there in August.

I can’t wait to get back and have several more trips planned this year …

References:

Saturday, 2 June 2018

Return of selene …

Small Pearl-bordered Fritillary (Boloria selene)




Apart from the unbearable temperature, the one thing I will always remember from the summer of 1976, was the abundance of the Pearl-bordered Fritillary Boloria euphrosyne and Small Pearl-bordered Fritillary B. selene. They appeared that numerous in my local woodlands that we took them for granted; after all they would always be there - or so we thought - and of course we were wrong. The last Small Pearl-bordered Fritillary of Sussex descent ever to fly in the county was seen on Saturday, 29th June 2013. At some point during the first week of July that year the species went extinct, both locally and regionally within Sussex.

The habitat requirements of selene and euphrosyne have historically demonstrated a degree of overlap and, on many sites, the two species used to fly together and they certainly did this in my old local hunting ground amongst the forestry plantations of Worth Forest in West Sussex. However, climate change has probably reduced this overlap and, more importantly, has most likely been one of the main driving forces behind the decline and regional extinction of selene.

Now the subject of a reintroduction programme, Butterfly Conservation’s Fritillaries for the Future project, it has recently, following intensive research by project leader Neil Hulme, been reintroduced to its former final outpost. Sunday, 11th June 2017 saw the successful completion of the first part of the programme when more than 400 selene were released as either final instar larvae or adults to Butterfly Conservation’s Park Corner Heath and Rowland Wood reserves and the Forestry Commission’s Abbot’s Wood. Early signs are encouraging with the habitat looking superb during my recent visits to Park Corner Heath and Rowland Wood. I look forward to returning soon. The above images (top to bottom) show (i) male underside, (ii) male upperside, and (iii), female upperside.

References:

Blencowe, M. and Hulme, N. (2017). The Butterflies of Sussex. Newbury, Berkshire: Pisces Publications on behalf of Butterfly Conservation (Sussex Branch), pp. 146-151.