Hartslock Nature Reserve is located on the north side of the Thames between Whitchurch and Goring-on-Thames, Oxfordshire. The site is owned by The Wildlife Trust for Berks, Bucks & Oxon (BBOWT) and managed by its staff and volunteers.
The reserve is a beautiful south facing, unimproved chalk downland hill with stunning views over the river Thames and the Goring Gap region. The grassland is surrounded by ancient hedges and mixed Yew woodland and, although it is only small (11-acres or 4.4 hectares), it is home to a very wide variety of plants and animals, some of which are extremely rare. For this reason the government has designated it and the surrounding area a ‘Site of Special Scientific Interest’ (SSSI) and the whole Goring Gap region is an ‘Area of Outstanding Natural Beauty’ (AONB).
The wildlife on Hartslock is typical of unimproved chalk downland but unfortunately, due to modern farming methods and the increasing pressures on land in the south of England, this kind of habitat is becoming increasingly rare.
Every 6 months I have a walk round the site with Martyn Lane, the BBOWT Oxfordshire Reserve Manager and my main contact within the Trust. The aim is to look over the site and make decisions on which work will be done in the next 6-12 months. It’s also a good opportunity for each of us to catch us and exchange news that relates to the site and generally take a look at how everything is doing up there.
The day was superb - gloriously warm and sunny - and the walk round was very pleasant - marred only by the fact that I forgot to take my camera so I have no photos!! Harlequin ladybirds were swarming in huge numbers at the tops of the hills but it didn’t matter where you stood on the site, we were brushing them off our clothes and faces the whole time.
Despite it being very late in the season I took my net and managed to catch quite a few tachinid flies: Tachina fera (one of the commonest and most easily seen summer tachinids), Eumea linearicornis (a late-season species) & Sturmia bella (a parasitoid of Small Tortoishell and other vanesids).
We decided in the end to continue work in slope 5 but also to reduce the height of scrub at the base of slope 3, where we did some work last winter. If there is any time after that we will try to clear around the edge of the orchid slope in readiness for a large project to replace and extend the rabbit netting. 
I can’t pretend that it was a glorious sunny day - it drizzled heavily all morning, once we had actually got over to field 5. But we stayed there and it wasn’t heavy enough to be too much of a nuisance and we managed to clear several areas in a large belt of bramble at the top of the hill. The aim here is to break up a continuous line of bramble and stop it becoming a thicket by removing any large shrubs and trees. At the same time we will expose the fenceline to allow routine maintenance
We had a great evening of mothing last night, with plenty of species coming in to the many lights - both actinic and mercury vapour. I will post a few photos and a list later.
However, for me, the big find of the night was a rare tachinid called Eriothrix prolixa, which I noticed in Ian’s Skinner trap early in the evening. It is not uncommon to find tachinids at moth lights - they tend to get flushed out of the surrounding grass and then get attracted to the lights with the moths. But it was the only tachinid I saw that evening but it was definitely something unusual because it stood and behaved quite like the much commoner Eriothrix rufomaculata but was much smaller and didn’t have any red side patches. You occasionally find completely black rufomaculata but under the microscope it was clearly different - having the hairy eyes, projecting moth edge, long spine on r4+5 and long costal spine - but with no petiole on the median vein.
We had a really excellent day for the August workparty and so we spent the time just strolling over the site, looking for Dodder and other interesting things. Dodder was very common across compartments 4 & 5 but a little less so than the exceptional year of 2008. Isolated patches also occur across the rest of the site.
Plenty of butterflies were seen, including: Clouded Yellow, Brimstone, Large & Small White, Common Blue (very common), Chalk-hill Blue (1 in compartment 4), Brown Argus, Dingy Skipper (second brood, 1), Small Skipper (1), Meadow Brown, Gatekeeper, Small Heath, Painted Lady (hundreds), Peacock, Small Tortoishell (3-4). Six-spot Burnets were very common, along with Silver-Y moths and a single Dusky Sallow.
During one of our frequent halts I managed to find a few species of micro-snail - Cecilioides acicula & Pupilla muscorum - both species live underground in soft, chalky soils and are no more than a few mm long. Being quite small they are easily overlooked but they are quite easy to find if you carefully scratch around in the side of ant-hills or where rabbits have scraped a patch of bare soil.
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Dusky Sallow on Scabious
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An interesting fungus in the beech woods
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a view from the top
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a pair of Six-spot Burnets
The weather in July has been really awful for insect-watching but I decided to visit the site on a mild, breezy and fairly sunny afternoon. At this time of year I like to stick to the first 2 fields because they tend to have the most nectar flowers and so attract a wider variety of insects.
There were the usual clouds of Painted Lady that we have got used to this summer, plus the usual browns and whites, with a few Peacocks and a lone Small Tortoishell. Common Blue and Chalkhill Blue were also seen on the Marjoram. But the star of the day was a single Silver-washed Fritillary, which soared out of Lower Hartslock Wood, settled for a while on some Knapweeds and then flew back into the wood after being disturbed by some passers by. We normally get Dark-Green Fritillary but I am pretty sure that this is a new species for the reserve!
Other insects seen: Tachina fera, Phasia hemiptera (male), Xanthogramma pedissequum, Chrystotoxum bicinctum, lots of Tiphia femorata on the unbels, Andrena hattorfiana on Scabious, lots of ‘ordinary’ tachinids like Exorista (rustica-group). Also a gorgeous, green metallic sawfly called Abia sericea, which was observed slowly feeding on a Wild Parsnip flower.
As I have said, the Marjoram was in full flower, along with plenty of Scabious & Knapweeds, Wild Carrot & Wild Parsnip, Clustered Bellflower, and a very nice patch of Dodder in full flower.
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Abia sericea (a sawfly that feeds of Scabious)
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Craneiobia corni (Dogwood Rivet Gall - caused by a midge)
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Craneiobia corni (underside of leaf)
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Dodder (parasitizing clustered bellflower)
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Dodder
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Courting pair of Eristalis hoverflies
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Exorista rustica-group (a tachinid parasitoid of sawflies)
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Phasia hemiptera (male, a tachinid parasitoid of grass bugs)
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Prosena siberita (a tachinid parasitoid of scarab beetles)
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Small White (pair)
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Tiphia femorata (a tiphid wasp)
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Xanthogramma pedissequum (a wasp-mimic hoverfly)
This month the ground was wet under foot from overnight rain but the showers relented in the main and it was a warm sunny day - ideal for wandering around and just observing things.
For me the best sightings were the Dark-Green Fritillary and the many Prosena siberita (a parasite fly which attacks small chafer/scarab beetles). The site looked wonderful though, with lots of Pyramidal orchids, Knapweeds, Scobious, Marjoram, Clustered Bellflowers, Centaury, Hairbells and thistles all over the site.Dodder and Bastard Toadflax were also showing very well.
Insects included Large Whites, Meadow Browns, Ringlets, Marbled Whites, Painted Lady, Comma, Common Blue, Small/Essex Skippers, 6-spot Burnet, Mecyna flavalis (a rare yellow pyralid), Pyrausta nigrita, Eriothrix rufomaculata, Tachina fera, Andrena hattorfiana and a few other interesting Diptera.
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Dark-green Fritillary
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Long-winged Conehead
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Prosena siberita
In the morning I ran a workparty at Hartslock nature reserve where I decided to just do a bit of tidying up. While strolling round I spotted an intriguing little moth, which I knew must be unusual so I took a photo. Back home I identified it as a red-necked footman moth (Atolmis rubricollis) - an unusual moth that is quite rare in our part of the country and so is likely to be a migrant - perhaps one that came over in the recent Painted Lady migration.
 Went up to the site today and found plenty of orchids in flower - the best of which were 6 Bee orchids (Ophrys apifera) in the main orchid slope - see photo. Very few Bee orchids across the rest of the site though so it looks like it is a bad year for them.
Thousands of Common Spotted orchids are in full flower and the Pyramidal orchids are just starting. The patch of Yellow Rattle that came in after some hay was dumped in field 1 seems to have spread a little and is flowering very well too.
Bristones, Meadow Browns, Large Skippers, Small Heath, Painted Lady & Marbled Whites were all on the wing too, with Banded & Beautiful Demoiselles. One each of Common Blue, Dingy Skipper & Green Hairstreak were also seen.
 Spent the day up on the reserve showing visitors around and the day was marked by clouds of migrating Painted Lady butterflies (see right). Every few seconds one passed by, heading north-west enroute from North Africa to who knows where.
One Lady orchid still looks very good as do half of the hybrids and most of the Monkey orchids. But recent bad weather does seem to have battered and dried a few of the flowers so they won’t be around for much longer I think.
Other highlights included a Green Hairstreak and some Dingy Skippers; lots of Small Heath and Common Blues. Courting pairs of Brimstones were also common. A few White Helleborines seem to have avoided the rabbits and deer too, in the Beech wood on top of the hill.
We also seem to have acquired a very friendly racing pigeon, which I found sitting at the top of the hill on the water trough. Not being a pigeon-fancier I decided to leave it to rest … but if you are missing a pigeon then you now know where it might be! 
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Latest news Winter season - lots of workparties to keep the scrub under control and sheep grazing in all compartments (on rotation).
NOTE: The workparty planned for the 10th January 2010 has been cancelled due to the snow.
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