This morning I counted 76, repeat 76, Brown Hairstreaks in 2 hrs 15 mins, of which about 30 mins were too cloudy for flight, at Shipton Bellinger on the Hants - Wilts border. I kicked off with 34 in 37 mins, but would have done better had I arrived 30 mins earlier (I got there at 8.50). Nearly all were males, in varying condition but including a number that seemed freshly emerged. I hit the last ball of my innings for 7 - the most I've ever seen together.
This is a personal record. In the past I've managed to get to 50 there, before the males conked out for the day.
Two questions. 1) Has anyone ever bettered this tally? (Neil Hulme need not apply). 2) Is Brother Betulae having a good year? (I've been quite pleased by numbers in N Wilts, but that population is not a patch on the Shipton Bellinger one).
The habitat at Shipton Bellinger is green lanes and hedges with abundant sloe on rough MOD-owned grazing land, on chalk, like this -
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I've not seen anything approaching that number in a day before, but Shipton Bellinger and Steyning Rifle Range (the best Hants/Wilts and Sussex sites) are like chalk and cheese. The differences are interesting, and the sites probably sit at either end of the scale in terms of both physical and population structure. Shipton is a 'landscape', over which your modus operandi is to survey for (predominantly) males, which appear to be widely distributed over assembly trees set within an extensive but generally unmanaged hedgerow system. Steyning Rifle Range is a small, compact site, set within a much larger, metapopulated area which is seldom explored, and into which many of our males must soon disperse. However, the Prunus stock on site is aggressively managed (all in a four-year coppice cycle), which acts like a magnet for ovipositing females. I think this is one of the main reasons (targeted observation of males being another) why we see so few males on site, but such large numbers of females - up to 23 individuals in a day. I'm not sure how easy it would be to construct an equation which could provide a meaningful comparison of male/female dominated data between these sites, but I do know who could - Rachel Riley from Countdown. We must employ her immediately.
"........into which many of our males must soon disperse."
I thought the perceived wisdom with this species was that the males assemble and the females also initially assemble and ultimately disperse to lay their eggs over a wide range.
Both the main Pembrokeshire sites are parts of meta-populations, albeit different ones. In my former stamping ground of Oxon/Bucks all sites were part of one extensive meta-population (visit Upper Thames Branch website to see how extensive). Is Shipton Bellinger unique in not being part of a meta-population or is it that nobody has looked for eggs in the surrounding countryside?
Yes, disperse from the very small area giving rise to such an unusually high population density on hatching (hence up to 23 females in a couple of hundred metres of hedgerow), 'manufactured' by aggressively managing the entire Prunus stock on the rifle Range on a four-year 'coppice' cycle, to assemble on ash and maple trees spread over a wider area than the confines of this compact site. It would make sense that individual 'Master Trees' have a maximum carrying capacity, before advantageous behaviour becomes disadvantageous. When the adjacent landscape is searched, largely by me, a more 'normal' scenario is observed, with plenty of males seen high in the ash, but a much lower number of females encountered.
I hadn't really thought about dispersing males... My assumption was that the males die off, leaving a long tail of egg-laying females. I suspect that individual ash trees do have carrying capacities - like small ponds and big male dragonflies.
No, there is a metapopulation covering a huge area around Shipton Bellinger. What's special about the network of lanes, hedges and chalk grassland scrub mosaics on MOD land west of the village is that there's plenty of dynamic invading sloe edge - no one trollops around with a flail cutter there.
I hadn't really thought about dispersing males... My assumption was that the males die off, leaving a long tail of egg-laying females. I suspect that individual ash trees do have carrying capacities - like small ponds and big male dragonflies.
No, there is a metapopulation covering a huge area around Shipton Bellinger. What's special about the network of lanes, hedges and chalk grassland scrub mosaics on MOD land west of the village is that there's plenty of dynamic invading sloe edge - no one trollops around with a flail cutter there.
Steyning is probably quite atypical in this respect. As a generalisation, I suspect that this species emerges at densities which are low enough to allow the majority of males to take up station on a favourable ash which is relatively close-by. In the Rifle Range 'betulae factory', if one assumes equal or greater numbers of males emerge (although complicated by the 'protandrous' effect, which perhaps even exacerbates the behaviour of the early glut of males here), the relatively low number of 'Master Trees' on the Rifle Range would soon become overloaded with tens of individuals. I generally see no more than 7 or 8 males per 'MT' (usually fewer), but would be interested in hearing how many others see elsewhere (per tree). At Steyning, they would only need to disperse several hundred metres to find a little more room, but by then are already out-of-sight of most visitors.
As Matthew points out, Shipton is a large rambling site, covering Tidworth, Cholderton and possibly extending much further afield than currently mapped. From my limited experience of Shipton, it is very much a metapopulated area, rather than a discrete site.
I am spending my recent butterfly days in seeking out High Brown Frits, Northern Brown Argus and Scotch Argus here in Silverdale and the wonderland of Cumbria. It makes a change from my previous years searching the hedgerows of the Bucks /Oxon borders to further our knowledge of the behaviours and presence of the Brown Hairstreak in the wider countryside of those counties.
In 2002/03 Dave Wilton and I took up the challenge of locating likely suitable habitat away from the known ‘hotspots’ (Bernwood, Otmoor and Whitecross Green), egg searching the blackthorn and in many successful cases returning to find the adults the following flight season. Local ash ‘assembly’ trees were easily found as part of this process which were visited the following season. This is now common practise in several BC branches.
Dave and an active team of UTB ‘eggers’ have built on this work with great success. Their endeavours have shown the BrH to be present in excess of 15 x 15 Km squares. The area is blessed with extensive hedgerows of blackthorn with much in suitable BrH condition despite the farming practices associated with the flail.
I visited Smardale Gill here in Cumbria Sunday last and tallied 214 Scotch Argus which was a very pleasing result. However for me the greater pleasure and excitement was following up a Sightings Page report of 7 SA located 2.5 Km further south in a parking bay on the very busy A685. Unlike the BrH the Scotch Argus is a relatively sedentary species so by what means had they taken up residence on such an unlikely spot? Many question as ever but very few answers?
I know that Neil and others in their respective counties are doing great work including Brown Hairstreak recording. I am familiar with Shipton and the Rifle Range from regular visits in near recent years and am aware of how they contrast as BrH habitat. It would be very interesting to hear reports on Ash Brownies of BrH findings further afield in the wider countryside in the seasons to come.
I desperately sought what might have been a final season’s High Brown sighting at two local sites here this morning. Alas I had to return to the diy with ‘null points’ with the further thought that you guys have the joys of at least another 4 weeks Hairstreaking.
In 2011 I had Brown Hairstreak in 8 Counties including Clare and Tipperary in Ireland. That might be seen as a challenge to some Ash Brownies in the coming season? You might be allowed to forego the Guinness on this occasion!
Quite seriously folks, a Brown Hairstreak turned up at Gait Barrows NNR (Lancs/Cumbria borders) some 10 days ago. The warden confirmed the sighting from photographic evidence. Have some of you guys been on holiday in these parts?
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