Weather - warm, breezy at times, one light shower, 19 degrees or so
After doing a bit of work in Bourne on Wednesday morning I took a mini-gamble with the weather and headed off for Glapthorn Cow Pastures to see the Black Hairstreak at arguably the premier site for this species in the country. My journey was not a good one from Bourne to the Oundle area - Northants. I got lost around Peterborough - again! I can't stand that place. The weather was clouding up all the time and a few spots of rain fell on the windscreen. I was beginning to think it wasn't going to be my day.
When I arrived at Glapthorn, a few patches of blue sky could be seen and immediately there was the faintest bit of sun. I walked up the main track and found the famous Dewberry shrub on the right-hand side, but could only see a Large Skipper on it. However, the sun came out a bit more and I walked further up one of the many tracks just to get my bearings - it being my first visit to the site. I couldn't see much going on so I returned straight back to the Dewberry bush and saw three Black Hairstreak's nectaring. Wonderful views but the day would only get better and better.
The Dewberry has pinkish-tinged flower heads compared to the traditional white flower heads of Bramble. Whilst rattling off a few pictures, I was joined by another couple and a gentleman called Thomas Spencer - an excellent butterfly enthusiast from Norfolk and with whom I spent most of the morning and afternoon chatting with. Thomas and I moved a bit further on to a larger area of Bramble which had Blackthorn stands high above and to the sides. Here, the Bramble has been strategically shaped so one can walk around it easily without getting snagged and photography was certainly aided by this maintenance work.
These four or five blocks of Bramble were the main nectaring area for the Black Hairstreak's and in total we saw at least 8 individuals. Some were slightly faded - I believe they had emerged a good week before my visit. However, three or four were absolutely pristine and the blue segment just below the tailstreamer is very noticeable in those fresh specimens. Thomas and I spent a good two hours or more watching their behaviour and movements and of course taking several photographs. Sometimes though, given the opportunity, it is better just to watch butterflies with the naked eye. I found they were very accommodating. We could get very very close in some instances, but when they were disturbed they bolted straight for the Blackthorn stands. Bramble is such an important plant and the Black Hairstreak seems very reliant upon it here at Glapthorn. They love a good fidget, moving around the Bramble head all the time to find the best pockets of nectar. I also witnessed a couple of them leaning to one side slightly into the sun, reminiscent of the Large Heath. They also like a good battle now and again. The victor usually returning to the chosen cluster of flower heads. When viewed at close quarters those little black-and-white striped legs are beautiful. A very compact and dapper butterfly. We also chatted with one of the local wildlife trust surveyors and he stated that this has been the best year for the species at Glapthorn since 2004.
All in all another great day. With the Black Hairstreak having such a short flight season, I only realistically had this one chance to see them this year. I'm so glad I took a punt on the weather. I believe the rest of June looks mixed.
This was another species first for me