Silver-studded blue day

Wednesday 3rd July 2024, Prees Heath

Prees Heath is a Butterfly Conservation reserve that hosts a colony of Silver-studded blue butterflies.

During World War II the site was used as an airfield. Post war most of the common was ploughed up and used for crops. It was purchased in 2006 by Butterfly Conservation who has have managed the heathland regeneration transforming it into what it is now. 

More information about the site can be found by following this link: https://www.preesheathcommonreserve.co.uk/

Arriving at the site’s parking area, at the sides of a rough track across the reserve, we found a second group had also arranged to visit the site causing a bit of a parking mayhem. Fortunately there was enough room for us all to fit in safely and not block access.

The track divides the site in two. The area to the north is by far the largest part and was the first area to be restored. The area to the south was restored quite recently.

Which way to go?

This was solved when the other group went into the northern area.

We went into the southern part! 

[This was my plan anyway, as our last attempt to look at this area was ended prematurely by persistent rain. But rarely do we do what I plan!!]

This area was a mixture of wide strips of sandy grassland and heather surrounded on two sides by woodland and the other two by the A49 and the track.

An early find was a Mottled grasshopper.

Photograph: David Williams

Then the shout we were delighted to hear in this year of very poor butterfly sightings, “Silver-studded blue”.

And there were, thankfully, quite a few of them.

The cool start to the day made them reluctant to fly and we were able to approach quite close to admire them. As the day warmed up in pleasant sunshine, they became more flighty.

Photograph: David Williams

We were pleased to see that they were keen to contribute towards the next generation.

Photograph: David Williams

As we continued our searches the main areas of interest were the grassland, the heather and the scrub around the edge.

It was in the scrub that we found a Ruby tiger moth larva;

Photograph: David Williams

And a Vapourer moth larva.

Photograph: Nigel Cane-Honeysett

Beating a gorse bush growing alongside the track revealed a Gorse shieldbug and a Green shieldbug.

This was followed by a Kentish snail, Monacha cantiana.

Photograph: Nigel Cane-Honeysett

Despite its regionalised local name it is established throughout most of England.

Examination of a bush of broom revealed this beetle:

Photograph: David Williams

Although we were unable to identify it in the field we should have known that it is a Broom leaf beetle, Gonioctena olivacea!

Returning from a trip to the far end of the site the photographer informed me that he had found the hoverfly Helophilus hybridus.

Photograph: Bob Kemp

This was followed by finding a largish click beetle, Agrypnus murinus.

Photograph: Nigel Cane-Honeysett

Unfortunately I am not sure when the next insect was found so now is as good a time to introduce it as any, a sawfly identified with 100% certainty by "AI" as Tenthredopsis coquebertii. 

Photograph: Nigel Cane-Honeysett

I look forward to being told if "AI" got it right.

For once lunch was a staggered affair. Somehow the usual telepathic call to gather for lunch did not happen. As a result, some had finished their supplies before some rovers had returned. And throughout this period discoveries were being made.

A Fan-bristled robberfly, Dysmachus trigonus.

Photograph: John Martin

The eggs and hatchlings of a Hairy shieldbug also known as a Sloe bug.

Photograph: David Williams

And a Common lizard.

Photograph: Liz Roberts

After this extended lunch break, we crossed the tracks to the other side.

This area was unexpectedly quiet, and we met very few other people. 

Venturing off the beaten track we made for eastern side of this area.

A Small skipper made an appearance.

Photograph: John Martin

Followed by a moth, identified as Gypsonama sociana.

Photograph: Nigel Cane-Honeysett

And another, Aristotelia ericinella.

Photograph: John Martin

Soldier beetles have been out and about for a few weeks but on this visit we saw our first of the later emrging beetle Rhagonycha fulva.

Photograph: Nigel Cane-Honeysett

This is a medium-sized red beetle whose elytra have a black tip. It is often found in pairs engaged in creation which has led to it acquiring the common name of Bonking beetle! It normally lives up to this name.

Leaf rolls were noticed on an alder.

Photograph: Liz Roberts

I believe that this was caused by the Birch leaf roller, Deporaus betulae, a weevil that cuts slits in a leaf, curls and glues the cut section into a roll, as in the photograph, then lays an egg in the roll. Normally it uses birch leaves but it is also found on Alder and Hazel.

Some conifers came in for scrutiny and yielded an Eyed ladybird (our largest ladybird) and a Scymnus suturalis (rather smaller). I will leave you to guess which is which in the photograph.

Photograph: David Williams

It was getting towards the end of the day and, remarkably, we all gathered around some grassy hummocks in a small clearing among a line of trees. Searching the neighbourhood of this area was rewarding.

A Slender-horned leatherbug, Ceraleptus lividus.

Photograph: David Williams

This is only the fourth time this insect has been recorded in Shropshire and Prees Heath is the furthest north it has been found in the county.

We then found a dead cranefly, Tipula unca. On its genital region there were two white blobs. What are they? It has been suggested that they may be eggs, possibly a Tachinid fly.

Photograph: Joahn Martin

Then we found a micro-moth, Eucosoma campoliliana.

Photograph: John Martin

Followed by a tiny moth which we could only able to identify as a species of Stigmella.

Photograph: John Martin

As we made our way off the reserve the larva of a Beautiful yellow underwing was spotted on the heather.

Photograph: Liz Roberts

And finally, a very striking hoverfly, Xanthogramma pedissequum.

Photograph: John Martin

A very pleasant day had been spent on a good site. The Silver-studded blues had put on a show for us, but, although we found a lot of other species the numbers of each was, like other sites this year, very disappointing.

BUT we did find one species that was new to the county, a frit fly, Thaumatomyia hallandica.

My thanks Butterfly Conservation for granting us permission to enjoy ourselves and to the photographers for providing their excellent images for this report.