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.
I have just got back from a lovely morning up on Hartslock where I can confirm that the orchid flowering season is definitely over. All of the Lady, hybrids & Monkey orchids have set seed or are very close to going to seed so if you haven’t come already then book a date in your calendar for the second/third week of May 2015. There are plenty of Common-spotted Orchids and around 100 Bee Orchids looking really exotic and the Pyramidal Orchids are just starting.
The rest of the site was looking really lovely with a profusion of flowers and butterflies. The first Large Skippers and Marbled Whites were out and a lone Clouded Yellow zoomed across slope 3, pausing to drink nectar from Dogwood flowers.
Dodder (Cuscuta epithymum) is starting to appear across the reserve but isn’t in flower so can be tricky to spot, while another rare and elusive plant, the Bastard Toadflax (Thesium humifusum), is flowering well across in slope 4 – accompanied by the Bastard Toadflax Bug (Canthophorus impressus)
Plenty of visitors came up to see the orchids this weekend, despite the wind & rain. I counted around 140-150 hybrids in full flower plus 1 Lady orchid. They are still mainly in the same square on the slope (A1) but there are a few outliers to the west and south, with a growing colony of healthy plants pushing into the woods outside the rabbit fence. We even found a potential hybrid seedling on the steps up through the woods!
Monkey orchids seem to be coming out nicely and most plants are fairly large and strong. There are still quite a few in bud so please watch where you are treading because they are very easy to miss and we want as many as possible to set seed this year. The colony is recovering from a succession of bad Springs (2 droughts followed by 1 exceptionally cold & prolonged) so plants on the more exposed southern face have been suffering disproportionately. There are a few flowering in this part of the slope but we have taken the decision to cordon this area off to allow the slope to recover without disturbance this year.
One Monkey orchid has been seen in flower in the first field, just down from the bench, but please be very careful not to tread on it because it is difficult to see. It seems to be the only flowering plant in this field this year. There are 2 more Monkey orchids below the beech tree on slope 4 with one in good flower. This satellite colony also suffered badly in the drought years so we hope that they will recover over the coming years.
This year the Spring feels very normal, with things appearing at about the right times and no big surprises. We have been finding about the same number of orchids as last year, with slightly more on the western slopes than the southern ones. This follows the trend since the 2 very dry winters/springs that we suffered a few years ago where many southern plants were killed off by drought.
We have just 1 Lady orchid flowering this year and it has just started opening its flowers and 1 hybrid opened about the same time from its sheltered position outside the fence in the hedge.
Lady orchid (Orchis purpurea)
Lady x Monkey orchid hybrid (Orchis x angusticruris)
Currently the gate is closed but I will hopefully be going up on Sunday (EDIT: now delayed until Monday) to lay out the marker tapes and after that the gate will be opened to allow visitors onto the slope from the lower field.
In addition to the orchids there have been sightings of Grizzled & Dingy Skippers and I bet there are also Green Hairstreaks out too, along the hedges. If you can catch a moment when the sun is out you should be lucky. They are also plenty of beeflies, cowslips, hairy violets and a few Pasque flowers over in field 4. The Pasques have been in flower for a few weeks and are being eaten by the rabbits quite badly this year but they are worth going to look at.
Today’s work party really felt like the first proper day of Spring with 17C and glorious sun. Four species of butterfly were seen on the wing (Small Tortoishell, Brimstone, Peacock & Comma) and there were plenty of Bombus terrestris queens out looking for nesting sites.
The first task was to deal with the willow tree by the entrance gate. This is a lovely old tree with a colony of rare Jet ants (Lasius fuliginosus) in the rotted base but the winds had broken one of the limbs off right down to the base. The broken half is hung-up over the lane while the standing half was looking very precarious, as though it might fall across our gate & fence. Obviously, we want to keep the stump with the colony of ants and we will have to deal with the broken half at some point. But we also have to make sure that the standing half doesn’t break away – so we decided to cut off a few of the higher growth to reduce the leverage.
The Monkey orchids are looking great with plenty in flower on the western face of the slope. The southern side is cordoned off to protect the slope from more compaction and erosion – there are only 1 or 2 plants in flower because 2 successively dry Springs in 2011 & 2012 have knocked them back a bit.
The Lady orchids and a few hybrids are starting to go over but many hybrids are still in good flower. As are a few of the White Helleborines in the wood at the top – and the few that have, for the first time, come up on the orchid slope at the top of the hill.
This weekend at last things seem to be moving! Lady orchids & hybrids are flowering well and the first Monkey orchids are starting to open but they have quite a long way to go. Next weekend should see all of the Monkeys opening but for now there are enough to keep most visitors happy. Pasque Flowers are still flowering in the middle of slope 4, beyond the beech tree.
Dingy Skippers, Small Heaths & Green Hairstreaks are common with Grizzled Skipper, Common Blue, Holly Blue, Brimstone, Orange-Tip, Large White, Peacock, Small Tortoishell, Large White & Small White also seen.
Popped up to the reserve on Saturday morning but the cloud soon rolled in and the chilly wind kept my coat buttoned up. The hybrids and the Lady orchids are flowering, but not as many (~30%) as I had thought there would be after seeing them last weekend. The cowslips and chalk milkwort is looking lovely and there are a few good butterflies – Green Hairstreak around the hedges, Dingy skippers on the lower slopes & Small Heath in the grassland.
Some photos from yesterday: