Neil Hulme

[PhilBJohnson]

While I'm plugging the book (only a few copies now left before it sells out), there's some discussion of how the risk spreading provided by split diapause timing in Small Tortoiseshell (thread: Early hibernation?; Simon-in-Kent) may have been affected by huge changes in the phenology of this species (p.199).

BWs, Neil

Hello Neil,

The Small Tortoiseshell's sensitivity to climate change.

Over the last few years in Lincolnshire, the over-wintered Spring Small Tortoiseshells, generally, have been noticeably fresher in appearance than those seen 2013 & 2014, when I lived in the South (Surrey). This butterfly is very special, in that it is annually 'double brooded' and over-wintered as an adult (imago).
I think that the emergence times of the over-wintering adults and time in flight before hibernation, can dramatically affect the species performance in the Spring.

Kind Regards, Philip

[Jack Harrison]

Let me speculate a little about the chalk Graylings.

The usual reason for catastrophic decline in a species is loss of habitat. I am not all that familiar with the South Downs but I get the impression (from comments here and elsewhere) that the habitat there remains good if not even better than a decade or so ago. So perhaps the decline of the Grayling is due to some other cause. Chalk Graylings aren’t a totally isolated race like that on the Great Orme but there might be some parallels.

Could chalk Graylings use a species of grass that doesn’t do well – becomes desiccated - in our warmer climate? Maybe it is in the process of changing to a different [species of grass] foodplant (compare Comma from hop to nettle) The chalk Grayling might be sufficiently different from heathland race that it is unable to withstand a disease or parasite attack as well. And no doubt, there are many other possibilities.

I’m sure you’ll work this out Neil but it could be that habitat maintenance isn’t the answer. Maybe we are seeing evolution in action – the chalk Grayling is doomed.

A final question: is there an equivalent of chalk Grayling in other parts of Europe that might offer some clues?

Jack

[Neil Hulme]

Hi Philip,

Our research for The Butterflies of Sussex shows that the (local) timing of the early summer brood of Small Tortoiseshell (first appearance and peak, measured over the period 2010-2014) has moved forward by an incredible 3.5 weeks, since the comparable five-year recording period (1990-1994). This probably means that an increasing majority of this flight now goes on to produce the late summer brood, with a decreasing minority now entering early diapause (risk spreading). Further north, where the phenological shift will be less extreme, the degree of risk spreading is likely to have been less severely impacted, so based on this theory the decline in Small Tortoiseshell should be less extreme; this is borne out by the national dataset.

Hi Jack,

"but I get the impression (from comments here and elsewhere) that the habitat there remains good if not even better than a decade or so ago"
Not at Deep Dean, where the degradation of the habitat is sufficiently profound to be visible via remote imagery.

"Chalk Graylings aren’t a totally isolated race like that on the Great Orme but there might be some parallels."
The Sussex chalk-based population is indeed now very isolated; the closest I'm aware of are probably those on the IOW.

The main foodplants (on chalk) are Sheep's-fescue and Red Fescue, both of which are drought-tolerant. One of two main problems is the increasing spread of Tor-grass, at their expense.

The spread of Tor-grass, and the reduction of newly created burrows, scrapes and scree patches (the other main problem), appears to be due to the decreasing numbers of the rabbit, probably reflecting the serious impact of lagoviruses.

BWs, Neil

[Matsukaze]

A final question: is there an equivalent of chalk Grayling in other parts of Europe that might offer some clues?

Jack

The Grayling has gone from being common to virtually extinct on the chalk in Normandy - as close a parallel to Sussex as you are going to get - though the decline seems to have set in a little bit later there.

Something similar has happened in Somerset - the Grayling used to be common on the Mendips but is now essentially down to two sites - Brean Down and Crook Peak - which have the thinnest soils and most bare ground. The butterflies here seem to be larger and paler than the Graylings I see elsewhere.

[Neil Hulme]

First The Bad News ...

Today (1 August) I started at Deep Dean, to continue monitoring Grayling numbers. With the help of several others I struggled to a deeply worrying tally of three (2m, 1f), all of which were quite old butterflies. The Sussex Grayling is in serious trouble, so any further sightings would be most welcome, and vital in determining just how critical the situation is. There's plenty more to enjoy up there, including numerous Silver-spotted Skippers and the first second brood Adonis Blues, so it's still well worth a visit.

Things were considerably better on the Park Corner Heath & Rowland Wood reserves, where I recorded a wide variety of species (25), including Small Pearl-bordered Fritillary (5, including 3 egg-laying females), Dark Green Fritillary, Silver-washed Fritillary, Wall, Painted Lady, Clouded Yellow, Small Skipper, Essex Skipper, Brimstone, Large White, Small White, Green-veined White, Speckled Wood, Small Heath, Meadow Brown, Gatekeeper, Ringlet, Red Admiral, Peacock, Comma, Small Copper, Purple Hairstreak, Holly Blue, Common Blue and Brown Argus. Two female Oak Eggar moths were sitting quietly on vegetation, while several males were seen flying at high speed.

[David M]

Just shows how difficult it is to properly conserve butterflies, Neil. Despite all your major successes lately, there are still some species on a spiral of decline.

Is there any likelihood of a concerted attempt to safeguard Graylings in Sussex over the next year or two? Seems like they need it!

[Neil Hulme]

Hi David

The Sussex Grayling certainly needs help, and quickly. I now have a much clearer view of what needs to be done, and how soon, but it remains to be seen whether this can be achieved; plans are being made.

BWs, Neil

[Neil Hulme]

Brownies And Small Pearls

Yesterday (6 August) I joined David Cook, Kirsty Gibbs and her (impressively patient) daughter for a Brown Hairstreak hunt around the Burgess Hill Green Circle. In all we saw the best part of a dozen males high in various master trees, with most being on the Burial Ground site. Four females were also seen in the master trees, with just one settling low in the shade of a Bramble for a few minutes. It wasn't until much later in the day that we finally found one egg-laying at the Batchelors Farm site.

Brown Hairstreak males have behaved rather differently to last year, when unprecedented numbers of freshly emerged butterflies were photographed low down, particularly at Knepp; not so this year. The big difference in behaviour has clearly been driven by this year's lack of nectaring opportunities. Although (now faded) males are descending to feed on Hemp Agrimony (where present) as it comes into flower, the thistles had already seeded due to the intense heat, and the Fleabane flowers were already 'dry'.

However, the behaviour of females has remained remarkably consistent. Although a handful of females have been seen in Sussex through late July, they have been freshly emerged individuals, soon retreating to the canopy. It is only now that the females are starting to egg-lay, to precisely the same timetable as in previous years. This has held true over the twenty year period surveyed by the 1990-1994 and 2010-2014 Sussex atlases; although we've seen some remarkably early males, the female Brown Hairstreak refuses to be hurried. Peak female activity is expected, as always, to be through mid and late August, but we should start to see a few more this week.

I then headed to our Park Corner Heath & Rowland Wood reserves, where there are plenty of Common Blues and Small Coppers to be seen, together with the odd Wall and Painted Lady. However, my target was second brood Small Pearl-bordered Fritillary, of which I saw four (3m, 1f). I had to wait until 7.30 pm before they finally closed their wings.

[Jack Harrison]

....the Burial Ground site.

Have you booked your plot Neil? Sounds a good place to end up. I have already paid for my patch at a Scotch Argus site

Jack

[David M]

The Sussex Grayling certainly needs help, and quickly. I now have a much clearer view of what needs to be done, and how soon, but it remains to be seen whether this can be achieved; plans are being made.

Thanks for that, Neil, and I wish you every success (similar to those you've achieved with your other target species lately).

It would be a great shame if you lost one after having resurrected the fortunes of others.

[Neil Hulme]

What A Difference A Day Makes

This morning (7 August), in the sweltering heat, I visited Steyning Rifle Range, hoping that the female Brown Hairstreaks had decided to started egging in earnest; they certainly had! Having blanked here just a couple of days ago, I found six at work in the thorns between 11.20 am and 1.40 pm, all in perfect condition.

I forgot one of the golden rules of hunting the females among the Blackthorn and Bullace - don't wear shorts! Finding them was relatively easy, but getting a clear shot at them, as they twist and turn on their journey deep into the shrubs, was not. In the end I only got a decent image of one, but there's always tomorrow!

Other highlights included a few Wall and some fresh male Adonis Blues. I always think that the start of the Brown Hairstreak egg-laying season marks the beginning of the end to another butterfly year, but I hope that we might see some exotics yet.

[ernie f]

But that one Brostreak pic you got was a cracker, Neil. It has to be worth a few blackthorn scratches. (next year you will have the pic but the scratches will be a distant memory)

[David M]

Perseverance pays off, Neil. You only need one to give you an audience to achieve the result you got.

Let's hope this species will be highly conspicuous over the next two or three weeks.

[Neil Hulme]

Thanks, ernie. The scratches have already healed and the grown-up trousers are back on.
Hi David. They were certainly conspicuous yesterday. A large group of hairstreak hunters turned up at Steyning and everyone filled their boots.
BWs, Neil

[Neil Hulme]

Brown Hairstreak And Small Pearls Go Large

The annual Steyning Rifle Range Brown Hairstreak festival is now underway, with the site performing spectacularly well yesterday (11 August). I arrived just after 11 am and spotted a pristine female sitting in the first stand of Blackthorn I approached, which was quickly joined by a second. The action came thick and fast and the combined efforts of a search team including Tom Parker, Gary Norman, Trevor Rapley, John Williams and James Arnott located a total of 16 egg-laying females, before activity ceased just before 2 pm. The majority were in perfect or excellent condition, although a couple of tattier examples were seen later in the session.

Gary and I then moved on to the Park Corner Heath & Rowland Wood reserves, to monitor numbers of the second brood Small Pearl-bordered Fritillary. We were surprised (and very pleased) to see more than we expected, and it was clear that butterflies are still emerging; four were so fresh that they must have emerged earlier that day. Despite weather conditions varying between unsuitable and borderline, we saw 11 individuals in a couple of hours. We only searched over the most promising areas, so I suspect there are a few more present. The top of the rush meadow, the W-E ride just south of the lake and the patch cleared of Bracken in front of the PCH hut were most productive. We were relieved to see plenty of fresh violets following the recent wet weather, providing a critical improvement in the breeding prospects for this second flight - just in time!

Plenty of other species were seen, including Wall, which seems to have gained a firm foothold here. I'm delighted by the rapid response of the wider butterfly fauna to the recent restructuring work.

[Wurzel]

Fantastic female Brostreaks Neil, something that has been hard to find at Shipton during the (at times) insanely hot weather

Have a goodun

Wurzel

[David M]

Beautiful images as ever, Neil. Brown Hairstreaks combined with fresh SPBFs isn't something we see every day!

Looks like betulae is gearing itself up now after a slow start.

[Neil Hulme]

Thanks, Wurzel and David. All of the good Sussex sites are now producing plenty of egg-laying females; it's hard to know where best to be!
BWs, Neil

[Neil Hulme]

Streaking Again

Another visit to Steyning Rifle Range today (13 August) produced numerous female Brown Hairstreaks, with some bursts of frenetic activity whenever the sun broke through. I didn't keep an accurate tally, but suspect I saw about eight individuals just in the vicinity of the fenced-off area of Prunus. Just after 2 pm I finally managed to get up onto the northern flank of the Rifle Range, where I found a further five in as many minutes. Although some are rapidly collecting nicks and scratches, several of those I saw were still in mint condition.

Some of today's visitors saw Brown Hairstreak for the first time, and went home very happy! My thanks go to the Steyning Downland Scheme volunteers for keeping the Blackthorn and Bullace here in such great condition for the butterfly.

[Neil Hulme]

More Brownies

Today (14 August) looked like a write-off for butterflies as the weather refused to live up to the forecast, but as I headed back towards home there appeared to be just sufficient sunshine to make a visit to Steyning Rifle Range worthwhile. It was getting on for 1.30 pm before I arrived, but for 45 minutes there was a flurry of Brown Hairstreak activity, with six different females being spotted by various members of the small group present; three others had been seen prior to my arrival. If the sun shines, this coming weekend should provide plenty of hairstreak action, and there should be plenty still flying for Richard Roebuck's guided walk here on 25 August.