The nice thing about the Northern Brown Argus in my area, apart from the fact that we have plenty of them, is that there is a great interest in them from locals and those who make Butterfly pilgrimages of many hundreds of miles. I have been very busy relaying information to visitors from all over the UK about where to look and when. In the process I have been more than happy to show people around some of the sites or just marvel from there e-mails and photos about how they had such a great day looking for this species in such an incredibly attractive setting such as the Berwickshire Coast is.
This season I was delighted to meet up with our very own Pete Eeles who has had great success in tracking down the larvae of the Northern Brown Argus. Pete was keen to look at favoured egg laying sites by females and took a series of photos of a particular Rockrose strewn banking marking the discovered egg laying sites on the photos in order that finding the larvae in spring may be made easier. Now....I have not actually found any of these larvae yet...but I do aim to rectify that with a intensive search in the spring....fingers crossed. I am a dab hand at Small Blue larvae spotting...surely it cant be so bad.
The Northern Brown Argus season kicked off much earlier than expected ( considering the cold spring) on the 28th of May. The emergence time can vary, but only by a few days. Numbers did not pick up until the 7th of June...which is about right for this area. By the 11th of June the season was in full swing peaking on the 25th of the month. Away from the coast in the Lammermuir foothills and Border hills the numbers peaked on the 29th of June, by all accounts, though it is always hard to tell as you keep finding fresh Butterflies right through July in little sheltered pockets. The last Butterfly recorded was the 24th of August. Quiet a lengthy flight season and about normal for the Northern Brown Argus.
A few problems this year involved Rabbit grazing pressure on some of the sites. Rabbits numbers were very high, highest I can remember, so vegetation was very heavily cropped. This put some pressure on the NBA colonies and females were forced to disperse further afield. As a result NBA were recorded some miles away from known Rockrose sites.
A few years ago now I was introduced to the work of Michael Braithwaite a now retired Botanical recorder for Berwickshire. In his 30 + years of examining the flora of Berwickshire he has written some outstanding books that chart the successes and failures of the past 30 years and more of our districts flowering plants. His books the " Botanical Tour of Berwickshire" 2013, and a "Short Flora of Berwickshire" 2014, were like lights being turned on in a dark room. I had up until that point not considered the flora of importance to what I do. How ignorant can I have been. With Michaels books I have managed to trace his rare plant finds to uncover Butterfly finds that have been jaw dropping. Little corners of the district that I never ever considered. On top of that I have gained a great interest in the flora myself spending as much time looking for rare Orchids and the likes as I do Butterflies. Anyway...to get to the point of all this. I noted a grid reference Michael had on the Whiteadder banks for Common Rockrose on a high scree embankment. He had visited many times, in fact many botanists had done so over the years and recorded several rarities....but never Northern Brown Argus. Naturally these were botanists, they were not likely to be looking for the Butterfly with as much focus as I would. So I decided to visit the site this year on the 7th of July. It was very overgrown and difficult to get to...but yes...a clear scree slope held an abundance of Common Rockrose. The slope was far to exposed and steep to search...so I looked in shelter at the top of the slope where Meadow Brown, Ringlet and Speckled Wood were hanging out.....and 1 silvery coin flipped through the grasses...a Northern Brown Argus...what an amazing sight. His books may prove to be the Rosetta Stone of further discoveries in the future...I think so anyway.
The photos below are from the coast and the little beaten up looking one is the Whiteadder discovery. Never has such a wee beaten up Northern Brown Argus looked so good to me.
Micheal Braithwaites Books can be downloaded for interest at
http://bsbi.org.uk/berwickshire.html