Friday, 11 May 2018

in search of the green hairstreak

My interest in butterflies started as subjects to take pics of while running. Just as I try to capture all the visual stimuli surrounding a run: the landscapes, skies and wildlife are what make it worthwhile to be out, beyond the huff and puff of a workout. (Which is why I don't do treadmills.) Butterflies are nearly all exquisitely pretty and the closer you look the more you see. Also they aren't as easily spooked as birds and often, with patience, you can get quite close to them. Making for better photos. I'd see one I hadn't come across before and google it; learn the name, and behaviours. Then I'd see something a bit rarer and wonder how to go about seeing it again. Previously, I left it to chance. Then I started to wonder how to come upon the local ones I'd not met yet. (There are about 30 Scottish species.) The excitement of getting a decent photo of a rarity is (I imagine) like an addict getting a hit.

So when I saw a ranger-led "survey" of Green Hairstreaks from Bonaly car park I signed up. Or rather I waited till the forecast was really promising and signed up. I had no idea what to expect but at worst it would be a 2hr stroll near Torduff in the sun. I biked up nice and early and hid my bike in the bushes nearby - no U-lock as I'd left it at Pressmennan. I took a photo of the blossom in the blue sky, what a perfect day!

Victor the ranger met us at the car park. He told us the GH hadn't been seen here last couple of years. So it was far from certain we'd encounter any. There were 2 sites to visit, the first being a few hundreds yards from the car park. We would look around the blaeberries (Bilberry), a low growing shrub, the foodplant of the GH caterpillar, that covers a lot of the low lying Pentlands.

Within 10 minutes I saw a small fluttering nearby and followed it till it settled, where I was delighted to claim the first sighting of the day. Although a bright iridescent green they are so close to the colour of the background foliage that they disappear very easily. We only really spotted them when airborne and even then sometimes lost track before they landed. The upper wing is drab brown, but you only see it in flight as they always close their wings on landing. They get the name Hairstreak from a thin line of white on the green underwing that is more often just dots or almost completely absent.

this pic to show how difficult they are to spot when landed
(dark "leaf" in centre of photo)

zoomed in

They seem to have lots of different habits and lifestyles in different parts of the country and reading about them in books and online is like hearing about a different species. They are also widespread throughout the country but localised into small colonies. I have seen signs advertising their presence at Tentsmuir but suspect if here is anything to go by you'd have to know where to look rather than just hoping to come upon them. Their size and colour made them very tricky to see. Someone would be pointing right at one and you'd not see it even though it was only inches away.

I moved about the area we were searching. Up to the left was a treeline and I was sure I'd heard someone say they'd only found GHs where there was blaeberries AND conifers nearby. A lot of the literature suggests they perch on branches a couple of metres off the ground. And yet the places we found them, especially the second venue, were bereft of trees and taller shrubs. The only butterflies up near the trees were sunbathing peacocks and fluttering whites.

almost no hairstreak (thin white line on hind wing)

From a reasonably successful first venue - maybe about 5 spotted - we moved uphill to an enclosed basin, which provided shelter and blaeberries. And was better yet - we must have seen another 15+ although it is very difficult to keep count and be sure it is not just the same creature returning to a similar area and being counted again. 

venue 2: 20yards on the left of this natural basin

If you want to see Green Hairstreaks best get out there soon they will be gone by late June. Like most butterflies they prefer sunny windless days. It was fairly windy while we were there, but I think the couple of warm sunny days prior to our survey was the reason we had success. The wind did add to the difficulties of getting a sharp shot. And I got at least one tick from lying in the undergrowth to take pics. However I was very pleased to have found this elusive creature and got some photos, and  to have met Victor the ranger, who will be leading a couple of groups in June to survey for the Small Pearl-Bordered Fritillary an absolute cracker and another I've never seen. 


  1. Congrats Pete!! Excellent finds and some beautifully marked ones too, well chuffed for you, you'll absolutely love the frits!

  2. Thanks Brian, I hope we have as much luck next time, I didn't know we had SP-B Frits round this way.
    Next target might be Small Blues: another cutie.