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At 15:52 we (Andrew Middleton and myself) completed our own challenge of finding white-letter hairstreak in all the 25 x 2km squares in TL20 in Herfordshire. Last year there were no records from this particular 10km square. It is mixed habitat of woodland, grassland and some largish towns with a scattering of villages and some very busy minor roads used as rat runs. We wouldn't say that this 10km square is particularly elm rich and much of the survey work was restricted to roadside and some parts there was only limited access to a particular 2km

In 2006 we had set ourselves a similar challenge (well it started in 2005) to find them in TL41 which we completed in the spring of 2007 with eggs in the two Essex squares. This had prompted us to set up our national project.

Anyway to keep it brief, we casually started in the winter with occasional egg searches and by the spring had completed 3 squares.

On the 8th June we went out and managed only 1 square before the weather gave up = 4
On the 15th June we managed to complete 7 before again the weather gave up = 11
On the 20th June I managed to complete one local to me = 12
On the 21st June we managed to complete 8 before looking for Purple Emperor (also successful) = 20
And today despite some heavy rain we completed the final 5 = 25 in total!

Although the weather hasn't been very good and quite windy, the moments of sunshine between clouds is to our advantage as a White-letter hairstreak becomes active almost immediately whereas if sunny all day, activity subsides!

Liz

Well done Liz
I'm seriously impressed with this systematic recording of an under-recorded species. I'd love to do something similar myself up here in Sheffield. Any tips on how you went about doing this? How did you pick your spots in each 2km square? Andonce there, how did you go about specifically identifying WLH eggs, larvae, and butterfly?
Paul

Just wade through this website and you should find all the tips you need.
http://www.hertsmiddx-butterflies.org.u ... /index.php

For starters you have to find the elm - without elm nearby no white-letter!
Liz

Excellent work Liz.

As an aside, this year I again reared around 30 WLH from ova through to imagines on non flowering elm with practically no losses. The ova were adhered by me to elm suckers and sleeved during the winter of 2010/2011 and followed right through to pupation and beyond.

The stock was local, and the resulting adults have now been released back from whence the stock originated.

Sadly however, several conservation groups with whom I am involved refuse to believe, despite much evidence (as well as the existance of populations which survive on non-flowering elm), that the species can survive (breed) on non-flowering elm regrowth. The fact that it can is significant in the conservation efforts directed towards this species and the prospect of roadside non-flowering elm regrowth as corridors to aid the species dispersal.

Piers.

Very interesting.

Having also reared WLH from ova, I've needed to (obviously) find suitable elm when the eggs hatched (I didn't sleeve them). At that time, I could find no leaf burst whatsoever; the only available food was elm flowers and perhaps this is a reason for some thinking that they need flowering elm. Personally, I think they just need food in whatever form!

Cheers,

- Pete

I wondered about this too Pete, and as the ova were sleeved out of doors (rather than taken from the refrigerator at a time deemed 'right' by me), I assume that the newly hatched larvae have the ability (much like their black, brown, and purple kindred) to bore into the swelling leaf buds and commence development from there. But it is only an assumption, founded upon the fact that the leaf bud is the only available source of nutrition at the time when the ova would have hatched.

I have little doubt that mature elm trees that produce a profusion of flowers are the preferred site for the female butterflies to oviposit where such trees remain extant. The fact does remain, however, that there are populations (perhaps satellite colonies, temporary or otherwise) that do survive (certainly oviposit) on 'English' elm regrowth which does not flower, and this does have implications upon the species ability to travel from one 'prime' locality to another. Roadside elm brash at Sopley and Winkton in Hampshire for example.

Piers.

Whilst surveying for the national project there were a few targets where only English scrappy elm was found. This would have been found in the spring and we would have noted it wasn't flowering. We returned in the summer and found adults - one particular example was in Berkshire.

We have a distinct adversion for looking for eggs on anything other than wych if we can, it is time consuming if nothing else so have to my knowledge never found an egg on scrappy elm. This doesn't mean to say an egg wouldn't be present.

Liz

Liz Goodyear wrote:We have a distinct adversion for looking for eggs on anything other than wych if we can, it is time consuming if nothing else so have to my knowledge never found an egg on scrappy elm. This doesn't mean to say an egg wouldn't be present.

They have certainly been found on such elm near Stockbridge Down, Hants. You are probably quite right though, in as much as people searching for ova would be more likely to search what would traditionally have been considered 'suitable' elm, usually wych elm. Similarly, people who hope to photograph the species probably in the main tend to congregate at known hot-spots rather than potentially 'waste time' searching stands of elm that are not already well known for the species.

Piers.

Similarly, people who hope to photograph the species probably in the main tend to congregate at known hot-spots rather than potentially 'waste time' searching stands of elm that are not already well known for the species.

Exactly - I couldn't agree more!
One of the points arising from our survey was where we found elm, everywhere, how many people would stand on a road verge (often with extreme difficulty in parking and some degree in danger) to look at some random elm in the middle of nowhere or even in the centre of an urban landscape just in case a single male decided to do a brief flight around the canopy or some adjacent tree! Not many I think.

Even searching in TL20 meant having to stop in odd locations to look. The worst is the planted elms (SAGs) as they are so often in school grounds.

Someone thought we were burglars the other week and had even noted my car registration number before I had the chance to speak to them and explain what we were looking for. They thought we had our binoculars on a house

Liz

Hi Liz
As a result of your original forum post, and then the weblink you posted in the reply, today I decided to visit the nearest White Letter Hairstreak site to Chester that had been surveyed randomly in 2007, and also in 2009.

The site is just outside the village of Milton Green, and the grid reference is SJ459587. According to the survey evidence, the best evidence of breeding was a hatched egg. I saw around 10-15 adults buzzing around the tops of some ash trees next to an Elm.

Only worry is that Dutch Elm disease was evident in at least a quarter of the 50 or so Elms at the location. And most of the 50 Elms were of the age that they become suceptible to DED. So I'm not sure how long the colony will last. Fingers crossed for their future.

So thanks Liz for the tip. I'm going to try to find some new locations next year, following all your tips.

Paul