27 Jul 2014

27 July 14 - Nearly A Hat Trick

It is now that time of year when Dorset people who are interested in Butterflies start talking in excited, almost reverent, tones about Alner's Gorse. This is a Butterfly Conservation reserve in North Dorset which is home to 3 of the 4 species of Hairstreak Butterfly that occur in Dorset. I wouldn't be surprised to hear that the Spring flying Green Hairstreak occurs as well. Even better, if you time it right you might see all 3 of the Autumn Hairstreaks on the same day. These 3 Hairstreaks are small, easily overlooked, species which often spend a fair bit of time in the treetops of the respective favourite trees, but will come down to nectar or sit on lower vegetation. At this point, they should be easy to see & photograph, but as they can sit still for relatively long periods of time, they are easily overlooked until they fly back up high again. Still it would be boring if all Butterflies were as easy to see as Gatekeepers. A couple of visits this time last year resulted in me adding all 3 species to my Dorset Butterfly list. However, I only managed to photograph 2 of the 3 species. So I was keen to go back again this year to try for Brown Hairstreak photos, as well as hopefully see the other 2 species again.
Alner's Gorse: Great looking habitat for Hairstreaks
Alner's Gorse is a good sized reserve and somewhere it would be possible to spend most of a day exploring. However, I had plans for the rest of the day, so had decided to try & limit my time there on this visit. I had heard that people had recently seen a Brown Hairstreak around the small car park, so I wasn't in a hurry to head off to explore the reserve. After spending about 10 or 15 minutes chatting with a couple in the car park, I suddenly spotted a female Brown Hairstreak only a couple of metres off the ground. She had probably been happily sitting there for longer than I had been looking. There was a quick dash back to the cars for cameras, before the chance for enough photography to impress a paparazzi photographer (except for the lack of a flashgun). But we had a real celebrity who knew how to pose for the cameras, rather than the self inflated pretend celebs the paparazzi seem to focus on.
Brown Hairstreak: Female. Females are a lot brighter than the males & have a larger orange patch on the upper forewing (not that I've ever seen the upperwings). I like the black & white banding on the feet and the bright yellow tips to the antenna (details I never notice in the field, but are very apparent on the photos)
Purple Hairstreak: Female. Looks like this one has been around for a while
Purple Hairstreak: Female. The purple is restricted to the base of the upper forewing, it would cover nearly all the upper forewing in a male
Purple Hairstreak: Alner's Grove (13 July 13). On its favourite Oak tree. Note, while the underside of the hind wing has a letter W where the white almost lines up with the white on the upperwing
Unfortunately, no sign of any White-letter Hairstreaks while I was there, but I a couple of tatty individuals had been seen before I arrived. So here is the White-letter Hairstreak from last year (taken with my little Lumix camera).
White-letter Hairstreak: Alner's Grove (4 Aug 13). Note, the underside is superficially similar to Purple Hairstreaks, but the letter W has the left side of the W sharply angled back towards the head
There are plenty of other Butterfly species present at Alner's Grove. I've seen 21 species without making too much effort over 3 visits at this time of year in 2013 & 2014 and there are a number of other fairly common species which occur at the site that I've not seen. Generally my visits have been focused around seeing Hairstreaks & I've not spent as much time as I should have exploring the wider reserve. Two of the other good species here are White Admirals & Silver-washed Fritillaries.
Speckled Wood
Having seen & photographed a Brown Hairstreak & had some bonus photos of Purple Hairstreak, I was keen to push on to the second part of my plan for the day: to look for a new Dragonfly on the Somerset Levels. You will have to wait for the next post to find out which species this was & how I got on.
Common Darter: The new Dragonfly is more exciting than this species