www.ukbutterflies.co.uk

Hairstreak Alley looks exactly the same type of habitat that I have seen Black Hairstreak before, eg Monks Wood, Glapthorn so it is reasonable to predict that if it does occur in other so-far undetected places in England, then the search can be confined to that type of habitat only. Might a winter egg search be profitable? Or is the habitat requirement so similar to that of the Brown Hairstreak that searches – with ‘null’ results – might already have been made? But no doubt Black Hairstreak eggs would not be quite so easy to find as the white ones of the Brown.

Jack

Hi Jack. I think it would be true to say that effective surveying for all habitat specialists involves the searching of only their optimum habitat type. The pioneering stuff is hard enough going as it is, so searching sub-optimal habitat would soon demoralise the keenest of surveyors.

Egg hunts for this species are not recommended as a way of assessing presence. Black Hairstreak eggs are 1-2 orders of magnitude more difficult to find than Brown Hairstreak.

BWs, Neil

Super Pupa

Today (16 June) saw another two highly successful guided walks at Ditchling Common, despite poor weather in the morning. Over the four sessions this weekend, Jamie Burston and David Cook managed to show more than 60 attendees the Black Hairstreak, with everyone holding a camera going away with photographs. A total of 15 hairstreaks were seen low down on the Bracken today, with much more activity above the Blackthorn thickets.

A chrysalis discovered by Ben Greenaway finally hatched, allowing a few people the rare opportunity to photograph a (female) Black Hairstreak next to its vacated pupal case. A great weekend was had by all.

Neil Hulme wrote:Today (16 June) saw another two highly successful guided walks at Ditchling Common...

Who'd have imagined this a couple of years ago? What a great opportunity for people to see this rare and elusive species.

They are clearly still emerging so there's plenty of life in their flight season yet!

More From Ditchling

The Black Hairstreaks of Ditchling Common were again entertaining large numbers of visitors yesterday (17 July). I was particularly impressed that one chap had risen at 5.30 am to travel up by train from Devon!

Unsurprisingly, numbers have been lower than last year, but very few enthusiasts have gone home disappointed. One thing we have learned this season is that this species will sometimes be active in the most unpromising conditions, with good numbers being seen down low on overcast, windy and even drizzly days. Activity levels start to subside in prolonged heat.

It is still possible to find butterflies in good condition, but from now onward it will be necessary to sift through an increasing number of individuals which are now beginning to lose their original shine.

Two 2019 Firsts

A brief visit to Fairmile Bottom LNR this afternoon (18 June) provided me with my first 2019 sightings of Dark Green Fritillary and Marbled White, although I have yet to see either species with their wings open! I found one of the former and two of the latter at roost under threatening clouds, but only managed to photograph the DGF before the heavens opened. I was very pleased to find Duke of Burgundy larval feeding damage on Cowslips in several locations.

Beautiful DGF, Neil. It's taken them a while to get going this year. In 2018 I saw several on 10th June.

Hopefully High Browns won't be too far behind.

Thanks, David. Here's another from this morning. There are now more than a dozen Dark Greens flying at Fairmile Bottom and Marbled White numbers are increasing rapidly.

The orchid flora here, which was superb until a couple of years ago, will hopefully improve again, as I've managed to broker a deal to get the cattle grazing reinstated, after a run of years without. However, I did manage to see half-a-dozen small Frog Orchids.

BWs, Neil

One of the oddest localities for Bee Orchids was/is on and around the crumbling runways of a WW2 airfield in East Anglia– I presume the concrete as it broke down reached alkalis of some sort. But the most bizarre aspect was that the colony of Bee Orchids extended into the soggy ground beside the old runways. The density of Bee Orchids and the total size of the colonies was quite the most impressive I have ever come across.

The owners / users of the airfield (including a – now deceased – knowledgeable botanist) were / are well aware of significance of their Bee Orchids but don’t want to advertise things for fear of the meddling by “do-gooders” from the conservation bodies. Things are just fine as they are.

I came across another airfield in the north of England, this time a damp grass field without runways, that had huge colonies of orchids (embarrassingly, I can’t recall the species but I think Bee Orchids).

My point is that Bee Orchids are not confined to calcareous grassland.

Jack

Neil,

Lovely photographs of the Black Hairstreaks. They seem to be flourishing over the past couple of years making them a much sought after species for us all. Nice to see the DGF on the wing too. Things are hotting up and not just next weeks weather.

Regards
Kev

Hi Neil ,
I reckon just missed you at Fairmile ,I had 3 bites of the Cherry (so to speak ) all early morning visits (6.30 - 8.30 am ) ,what a fantastic site !!
Like yourself I found 8 Frog Orchids ,but after visiting them once I was loathe to return ,as I was frightened of treading on them ,so left them be.
Very pleased to find them !! I also managed 3 Bee Orcs (inc ,1 weather beaten White one ) , also found several Fly Orcs ,and of course Pyramidal
Orcs (just coming into flower ) and hundreds of Common Spots ,including a type that I,ve never seen before ,it had the standard top flower clump
and then halfway down the stem ,another part flower head ………...very unusual .
On Tuesday morning we stopped in at Ditchling , for Black Hairstreak ,and was lucky enough to find a pair (in-cop ) ,which I showed to 3 other
butterfly folk that were there ,I reckon we saw about 6 , a lifer for me so well pleased !
Back at Fairmile ,I saw 1 Dark Green male ,numerous Meadow Browns ,Small Heath ,Large Skippers ,half a dozen Marbles , (my first for year )
Single Male Common Blue ,single Grizzled Skipper ,Ringlet (1st ) Painted Lady,also a very unusual 5 spot Burnet .
Had 3 "goes" for Silver -Studs(At Stedham ) ,the first 2 attempts were aborted in the car-park (Rain ) but finally cracked it yesterday and found high numbers on the wing including a pair in-cop .
On the way back to Kent this morning we again stopped in at Ditchling and were treated to some nice views ,but they were reluctant to come down low, also met Dave Cook there and had a natter ,good to meet him . No luck with the Club-tails though ……………..good excuse to go back !!
Regards Allan.W.

Hi Jack. Although Bee Orchid is usually associated with calcareous grasslands, it does sometimes grow on neutral soils. However, as I live on the South Downs I see 99% of mine on the chalk.

Thanks, Kev. The Black Hairstreaks of Ditchling have quickly gained superstar status! We've had hundreds of visitors from all over the UK this year.

Hi Allan. I'm glad your visit went well. If you thought that Fairmile was impressive, I reckon you should revisit in future years. The site is currently at a bit of a low ebb, but once the cattle grazing reconditions it, the orchid flora should increase by an order of magnitude! A few years back it was exceptional, and I'm sure it will be again.

BWs, Neil

Rarity At Knepp

Yesterday (21 June) I saw a real rarity at the Knepp Wildland - a Small Tortoiseshell laying eggs on young nettle shoots. Following the modest number of post-hibernation butterflies at Ferring Rife, this was only my third sighting of first brood individuals this year. I believe that this species has a grim future in the South of England, courtesy of climate change. No sign of the eagerly awaited Purple Emperor yet.

Lovely shots of the Small Tort Neil I don't share your pessimism as in my area they're pretty numerous still with similar numbers at my work for the last couple of years now - it may be a West/East divide as I know that Philzoid reckons that they're difficult to find in Surrey for example

Have a goodun

Wurzel

I hate to rain on your parade, Neil but, where I live at least, Small Tortoiseshells seem to have few problems getting to this stage. There are plenty around where I live at the moment, for example. But there seems to be a problem getting this generation through the immature stages, to produce adults the same year. Certainly since 2013, I have had plenty in late June early July, then almost nothing after.

Neil Hulme wrote:Yesterday (21 June) I saw a real rarity at the Knepp Wildland - a Small Tortoiseshell...

I live in inland East Sussex, between the South Downs and the Ashdown Forest. Small Tortoiseshells have been a rarity here for several years. I've seen none in and around my village this year, and last year I saw only 2.

Oddly though, the only Small Tortoiseshell I have seen in Sussex this year was at the end of April, at Knepp!

Hi Wurzel and Mark. I'm afraid we'll have to agree to differ on this one!

The vast UKBMS database (from 1976 onward), based on the national transect record, shows a 78% decline over the 43-year series, a 22% decline over the last 10 years, with 2018 ranked 41st. Bearing in mind that this is the nationwide record, which smooths out latitudinal differences, it masks just how serious the situation is in the South of England. Regional data shows the decline of the Small Tortoiseshell is generally less serious as one moves north. A quick and dirty analysis of some Sussex data suggests the decline here over that period is >90%.

I also pulled out the single species transect (max) counts of post-hibernation adults at Ferring Rife - the best site in West Sussex:
2013 - 194
2014 - 77
2015 - 64
2016 - 18
2017 - 33
2018 - 47
2019 - 14

The way we perceive the fortunes of a species depends on may things, including how far back individual memories extend. Malcolm Farrow, who is of similar vintage to me, posted this in response to one of my BC Sussex tweets: "I grew up in Sussex and, when I first began to take an interest in butterflies in the early 1970s would regularly count 20-30+ small tortoiseshells at a time on the buddleia in our garden. Now I’m grateful just to see one, as I did today."

This fits with my experiences of a time when the Small Tortoiseshell was common - more than 5 on a single Sedum spectabile; more than 30 on a single Buddleia; more than 100 on a walk in mid-late July (which was the peak of the first brood in the period 1990-1994 - an event which had shifted forward to late June by 2010-2014); at least half-a-dozen dead in spider's webs in the garden shed; and large aggregates hibernating in any outhouse.

I think we have to be wary of 'shifting baselines' - which even includes the 1976 date against which most scientific studies are measured. We have become used to Small Tortoiseshell being relatively rare, so I'd be interested to hear what "pretty numerous" or "plenty" means to others. These days I see far, far more Pearl-bordered Fritillary, Duke of Burgundy, Wood White and Purple Emperor than I do Small Tortoiseshell, and they are considered rarities (to a greater or lesser extent). This would have been considered unthinkable when I was a kid.

I believe, as does Jeremy Thomas (pers. comm.), that climate change is behind the problems faced by Small Tortoiseshell. I've previously posted on this subject viewtopic.php?p=140248#p140248 With the extraordinary forward shift of this species' phenology I believe there is an increased tendency within the population towards bivoltinism, with a consequent decrease in its risk spreading strategy (early hibernators). Here, I agree with Mark - the increasing risk comes with the next breeding cycle, and the increasing chance of desiccation of the nettle-beds, courtesy of climate warming. We saw this last year - the 'common' nettle-feeders suffered a stinker.

It's important to separate out climate change from shorter term weather effects. Only a few years back the species rallied strongly for a couple of years, only to fall back again. Small Tortoiseshell is likely to fight rearguard actions in cooler, damper summers, but this has to be set against the longer term backdrop of decline. Sadly, the data only points one way.

BWs, Neil

Fritillaries And Clearwings

Yesterday (22 June) I met up with Gary Norman for a very pleasant few hours at Park Corner Heath and Rowland Wood. Highlights included a very late Small Pearl-bordered Fritillary, a couple of Silver-washed Fritillary and a Dark Green Fritillary, but despite our best efforts we couldn't locate a White Admiral. Small Skippers are just starting and, bearing in mind the way the vegetation is now developing over the new rides, could become very numerous here.

We also bumped into Derek Barber and his partner, who were waiting patiently beside clearwing lures. I was delighted to see my first Yellow-legged Clearwings - very exciting!

The Ladies Are Coming!

This morning (23 June) I visited Littlehampton Golf Course to look for White-letter Hairstreak. They're only just starting here, with just five males seen in the canopy. Later visits to Eartham Wood and Fairmile Bottom were met with variable success, with neither White Admiral nor Silver-washed Fritillary at the former, but plenty of Dark Green Fritillary and Marbled White at the latter. However, Painted Lady was seen at both sites, with about ten at each. As many others have reported on the BC Sussex website, we're enjoying a significant influx.

Without considering the data I still have to agree Neil with regard to the Small Tortoiseshell. I remember seeing plenty of Small Tortoiseshell on the Buddliea at the bottom of my garden in the late 70's/early 80's. Living all my life in London has probably magnified the situation, with naturally far lower numbers naturally anyway but I went for many years without seeing a single Small Tortoiseshell. It was only when I moved to north east London that I started seeing them again. What I now consider a hotspot, Tottenham Marshes, can produce 5 or 10 post hibernators, (I'm not often there during the summer so I can't comment on first gen numbers), which looking back to my childhood years is pretty pathetic.

Obviously there will be isolated pockets which will produce the 'perfect storm' of conditions more often than surrounding areas which may mask the true, wider situation and us butterfliers do tend to gravitate to these places so perhaps some of us are guilty assuming things are better than reality. Perhaps Wurzel's situation, being further west and therefore having a higher average rainfall is also masking the overall situation?

A couple of weeks ago I was in Farnham in Surrey and came across a damp meadow/cattle pasture with a patch of nettle. Instinct told me it looked good for Small Tort and low and behold I found three larval webs plus a few fresh emergents so at least four batches of eggs were laid here. If I grew up here and didn't travel further afield and this is a normal occurrence I would probably assume things were ok for the Small Tort. The fact that I spent half an hour here chasing the adults and searching for more larval webs tells me quite the opposite sadly.