Eight species to look out for at Cothill Pitt
Small blue butterfly (Cupido minimus)
The Small blue butterfly (the Save Cothill Pitt logo) breeds in a range of dry sheltered grasslands where Kidney vetch grows, including: chalk and limestone grassland; coastal grassland and dunes; and man-made habitats such as quarries, road embankments and disused railway-tracks. Sites are usually sheltered and contain sparse or eroding vegetation where Kidney vetch seedlings can become established and where flowering plants are abundant. The best habitats typically contain a mosaic of short and tall vegetation, and patches of light scrub. The intrinsic low dispersal ability of the Small blue will restrict recovery, especially in highly fragmented habitats that remain outside the core areas of southern England.
Marbled white butterfly (Melanargia galathea)
Another butterfly of interest at Cothill Pitt is the Marbled white. It is a grassland species and can be seen in large numbers on sunny days between June and August. As for the Small blue, for it to thrive it requires unimproved tall grassland that is not intensely managed or over-grazed. The sheer numbers of this butterfly at this threatened site is an indicator of good habitat quality combined with an abundance of essential food resources such as the Red fescue grass, Festuca rubra, and the size of the area. Larger sites produce sizeable healthier populations that are ‘buffered’ to a greater extent from environmental perturbations that could wipe out smaller colonies.
Six-spot burnet moth (Zygaena filipendulae stephensi)
One of the more colourful and interesting day-flying moths at Cothill Pitt is the Six-spot burnet moth. It too depends on flower-rich grasslands (on light soils) that are not intensely managed. The larvae feed on Bird’s foot trefoil, Lotus corniculatus, and the adults obtain nectar from flowers such as Field scabious and Knapweeds. They do not occur in places where cutting or grazing reduces the height of the sward. Although it is considered to still be a ‘common’ insect this status does not reflect the fact that since world war two the amount of suitable habitat has been reduced by 98% nationally. Perhaps a revised designation for it as being ‘formerly common’ would be more accurate.
Brassy longhorn moth (Nemophora metallica)
The Brassy longhorn moth is easily recognised by its enormous antennae that in the males can exceed body length by 250%. It is only found where its foodplant, Field scabious, grows. This uncommon moth feeds as both a caterpillar and as an adult on this single host plant and so the loss of Cothill Pitt and its abundant Field scabious plants will probably result in the disappearance of this fascinating species. The impact of building houses at Cothill Pitt will be detrimental to this species in the wider area because the critically important metapopulation may be reduced in size or entirely lost.
Note: image shows Brassy longhorn moth (top) and Thick-legged flower beetle (bottom)
Large scabious mining bee (Andrena hattorfiana)
Cothill Pitt provides an important refuge for the distinctive Large scabious mining bee. This bee also requires an abundance of Field scabious, Knautia arvensis, flowers, and no other species, on which to drink nectar and collect pollen, which it feeds to its offspring. This photograph shows the characteristic salmon-pink pollen grains on the bee’s hind leg ‘basket’. Cothill Pitt represents a significant metapopulation of this large bee where it is at its most abundant for some considerable distance. Further afield this insect is encountered much less frequently and is never seen if its foodplant is absent.
Great green bush cricket (Tettigonia viridissima)
The spectacular Great green bush cricket is one of Britain’s largest insects, growing up to 55mm in length. Despite its large size it is well camouflaged and consequently it is more frequently heard than seen. Its ‘song’ is particularly loud and can apparently be heard from the inside of moving vehicles. It will feed upon the caterpillars of butterflies and moths when it finds them although it will also graze on plants if these insects are not available. It will also bite people who pick it up so it is best admired from a little distance. It requires light soils in sunny locations for egg laying because it is unable to force its ovipositor into heavier substrates. Although it is listed as ‘common’ it has undergone a marked reduction in range in the last 50-years.
Green woodpecker (Picus viridis)
Also known as the 'yaffle', the Green woodpecker is the largest of our UK woodpeckers. Unlike its spotted cousins, the Green woodpecker spends a significant amount of its time probing for ants in and among the grass. When disturbed it will often fly up, showing its superb green plumage and flash of red on the head of adult birds. Listen out for its cackle or laugh-like call.
Barn owl (Tyto alba)
The Barn owl requires extensive hunting grounds to meet its needs and the low, tussocky grassland at Cothill Pitt is perfect for just that. Barn owls do not hoot (that will be a Tawny Owl) but you'll know when you've seen one with its near-white plumage standing out in the low light of early morning or late evening. Although this bird is on the Amber list due to declines in numbers, Barn owl foraging habitat has no protection from development as such. However, planning authorities do need to take biodiversity into account when considering applications. Have a look at the Barn Owl Trust website if you'd like to know more about these wonderful birds and issues around their protection.
Insects, birds and other wildlife at Cothill Pitt
Written 2014 by Dr Bob Eeles
During a walk across Cothill Pitt on a sunny day it will quickly become apparent that this site hosts an abundance of flowering plants and that day-flying insects such as butterflies, moths and bees are present in enormous numbers.
Invertebrates at Cothill Pitt are very diverse and very abundant overall, in marked contrast to the majority of habitats in the locality. This is a reflection of the site’s high plant diversity and its soil structure and composition. The sandy-soiled site is generally free draining and there are gaps between the plants where seedlings can germinate and grow without intense competition. This is important to species such as the Kidney vetch, Anthyllis vulneraria, that can only thrive in such places and which is the only foodplant of the declining and UK Biodiversity Action Plan Priority species, the Small Blue Butterfly, Cupido minimus (our wonderful logo!).
A host of rare and common bees and wasps are also present, many of which require open sandy soils in which to make their burrows and reproduce successfully. Such habitats are becoming increasingly uncommon as sites such as Cothill Pitt are taken up for housing and other developments or which are intensely managed for livestock and arable crops. The significant decline in the availability of habitats of the right quality has led to a decline in abundance and distribution of many increasingly rare invertebrates and plants throughout Britain. This is why Cothill Pitt is of great significance to wildlife across the region. Such sites provide what are known as metapopulations.
These core ‘source’ sites enable species to survive in the wider landscape, at lower densities, by producing colonists that are able, subsequently, to occupy new areas. The likelihood of an invertebrate dispersing successfully to a new area depends on its degree of mobility. Some such as the very common Large Yellow Underwing Moth, Noctua pronuba, are very mobile and cover large distances whereas others such as the much rarer Small Blue Butterfly remain comparatively immobile and may not disperse further than forty or fifty metres from their places of emergence in most years.
The land features at Cothill Pitt are also important for birds. Expect to see Crows in the tall trees at the margins, listen out for the tell-tale call of the Chiff-chaff in summer and watch blackbirds feasting on blackberries along the top road. In the more open heart of the old quarry, you may be lucky to catch sight of the largest of our woodpeckers, the Green Woodpecker or perhaps just hear its characteristic laughing-style call. And if you want to stand a chance of seeing a ghostly glimpse of the local Barn Owl, swooping over the tussocky grass in search of small mammals, you'll be best take a walk at sundown or very early in the morning.
Sandy sites such as this are also classic spots for sun-loving reptiles such as lizards, grass snakes and slow worms.