At 10.30 on a damp night in late June, people in Barnack may have wondered at a mysterious glow on the Hills and Holes. It came from the light of a dozen torches held by a group of Friends of Barnack Hills and Holes, led by Chris Gardiner, from Natural England. They had come to find a more fascinating light – that of our native glow-worm.
The glow-worm, Lampyris noctiluca, is not a worm but a brown beetle up to 25 mm long. It glows at all stages of its life (egg, larva, pupa and adult) but it is only the wingless female that glows strongly. The light-producing organ is on the underside of the tip of the abdomen and contains a layer of the chemical ’luciferin’, backed by a reflector of minute crystals. Luciferin glows with a cold, greenish light when combined with oxygen, and the glow-worm is able to turn the light on and off, possibly by regulating the supply of oxygen. The sedentary female glow-worm lights up strongly for a few weeks in summer, to attract sharp-eyed, winged males. As well as attracting a mate, the glow is a warning to predators: glow-worms taste bad and can cause vomiting. Adult glow-worms rarely feed, so after mating the female turns out her light, lay eggs and dies.
The eggs hatch into larvae after a few weeks and remain as larvae for one or two further summers. The larvae are greyish-brown, with yellow triangular markings on their sides. They are predators, feeding on small snails and slugs, which they grab with their jaws, inject with digestives juice and ingest as a mush. It is no coincidence that limestone grassland, which supports large populations of snails, is a favourite habitat of the glow-worm, although the insect can also be found on road verges, along hedgerows and in gardens. The decline in glow-worm populations in the last half century is linked with the loss of much of Britain’s chalk and limestone grassland. Another problem for glow-worms is competition from street lights and other light sources, which disrupts mating behaviour by attracting males away from the glow of the females.
Although the weather was not ideal, the Friends did find glow-worms that night in June. The glow was unmistakable, pin-point sharp and surprisingly bright. Once the rain started in earnest the reflection from the raindrops on the grass caused confusion, so the party called it a night, feeling well satisfied with the outcome of the expedition.
There are a few Frog Orchids at present, only about a dozen I believe. They are in one of the protected areas and if you want to see them please ask the warden when you see him on site.
The frog orchid, as the latin name viridis suggests, is green in colour, which in combination with its stature makes this species a difficult plant to find. However, if you are lucky enough to catch it in flower you will see that the flowers live up to its name – resembling small frogs on the stem. In common with other orchids the flowering of frog orchids is uncertain and may vary from year to year.
A hardy group of 14 friends surveyed the south-west compartment for man orchids on a very wet Saturday morning. Completing three traverses of this area of the reserve spread out in a line we managed to count and record the location of 161 man orchid flowering spikes. A significant increase in numbers on surveys in recent years but still significantly less than the peak recorded in the 1980’s. The survey only covered one sector of the reserve and casual walks along the main paths in the north west compartment can also find man orchids in flower. The previous post shows what we were looking for and the orchids are still flowering and can be seen on the reserve with a little care and time to hunt out the green/brown spikes from the green/brown vegetation! If the sunshines it is an added benefit as the butterflies will also be out, they were notably far more sensible than us and avoided a soaking!
Orchis anthropophora, the Man Orchid, is a European species of orchid whose flowers resemble a human figure. The head is formed by the petals and sepals, and the suspended torso and limbs by the lobes of the labellum.
It is fairly rare and is just coming into flower on the Hills and Holes. Very small at the moment, flowers just starting to form
This composition shows on the left, the Orchid in its natural environment, and to the right of the frame, a more-detailed bokeh shot.
May is surely one of the best months on the Hills and Holes – the pasqeflowers out in their full glory, set off by bright yellow cowslips and this year a good show of early purple orchids.
As the month progresses many other flowers come into bloom, including one of the site’s great rarities, the man orchid. A count of this species has been organised for 24th May, when we hope as many Friends as possible will join us.
May is also a good month for butterflies – you should see familiar species such as tortoiseshell, comma, peacock and brimstone waking from their long winter hibernation.
They are joined by freshly emerged spring species such as orange tip, holly blue and speckled wood – this is likely to be seen in the wooded area next to Walcot Park.
One of the hardest to spot butterflies is the green hairstreak, whose green and brown colouration helps to camouflage it against the hawthorn and other shrubs where it flies. Birds are also busy at this time of year. Many of the birds breeding in the Hills and Holes are associated with scrub and wooded areas, including blue tit, great tit, blackbird, dunnock and willow warbler.
Enjoyed a day out with the Peterborough Conservation Volunteers on Sunday 13th April.They work on various local nature conservation projects. At first sight removing new growth of Silver Birch, Hawthorn and other new bushes and trees may seem more like destruction than conservation.Unfortunately, if these bushes and trees were left undisturbed,they would grow to cover too much of the Hills and Holes and the flowers which currently carpet the open area would decline. In the Hills and Holes it is the open limestone landscape that is being conserved so that its particular habitat can continue to support its rich population of plants and wildlife . The weather was fortunately dry and mild. The outdoor work was enjoyable and fellow workers seemed to have plenty of information to pass on about findings on the reserve as work progressed. Due to the need not to disturb birds and other wildlife during the spring and early summer months it seems that they will not be further working parties like it until late summer but I shall be awaiting their future programme with interest.