The plants of the clearings are pastel blues, pinks and purples with a smattering of stark yellows and whites. They include: common centuary (Centaurium erythraea), field scabious (Knautia arvensis), greater knapweed (Centaurea scabiosa), harebell (Campanula rotundifolia), hedge bedstraw (Galium album), marjoram (Origanum majorana), milkwort (Polygala calcarea), mouse-ear hawkweed (Hieracium pilosella), squinancywort (Asperula cynanchica), stemless thistle (Cirsium acaule), wild basil (Clinopodium vulgare), yellow-wort (Blackstonia perfoliata) and quaking grass (Briza media). Eyebright (Euphrasia sp.) and wild thyme (Thymus polytrichus) are largely confined to fine-soiled anthills.

The chalkhill blues (Polyommatus coridon) are out and keep low, looking almost white against the sward; the marjoram seems the preferred nectar source; there is little though of the larval food plant, horseshoe vetch (Hippocrepis comosa). The caterpillars are also protected by ant species which offer them some protection from predators and parasitoid wasps in exchange for sugary secretions from a special gland. The vetch, the ants and thus the blue require hard-grazed (or mown) chalk grassland and hence only exist together in isolated patches of managed nature reserves within dead seas of arable land as well as unsuitable scrub and woodland. The butterfly is, like many other species with specialised habitat requirements, ‘conservation dependent’; a status greatly assisted by its pale beauty.

Male chalkhill blue on marjoram.

Coincidentally and unsurprisingly, the chalkhill blue was nominated as the  “Insect of the Year” in 2015 for Germany, Austria and Switzerland. A recent review states that ‘genetic patterns strongly support the existence of ice age refugia in Italy and in the Balkan Peninsula at least during the last glacial period.’ Other such refuges are also found in the Pyrenees and Iberian Peninsula. The species expanded its range as the climate ameliorated and presumably as pastoral agriculture spread north especially along the great river valleys. Analysis of genetic lineages provide road maps of the route marches across Europe and Asia along sinuous corridors over thousands of years. Today, the scattered pockets of population of this remarkably resilient butterfly, like so many other species on the edge of their range in Northern Europe, are perhaps no more than beleaguered outposts; abandoned Roman legions still fighting to hold the hills in a landscape long lost to Vandals and Visigoths. Recent evidence suggests not; the English population has expanded since the 1980s in response to conservation management and warming summers. The remnant populations on the tops of a few chalk hills are proving to be modern refugia. The only niggling question is how are the ancient core populations in Southern and Eastern Europe faring since they do not receive very much conservation attention at all?  If the extensive karst landscapes of Montenegro are anything to go by, the species is likely to be thriving in parts.

Common blue (Polyommatus icarus), brown argus (Aricia agestis) and a fleeting holly blue (Celastrina argiolus) buzzing the ivy (Hedera helix) hedges are also here. A silver-washed fritillary gallops through and brimstones (Gonepteryx rhamni), skipper species (Hesperiidae) and six-spot burnet moths (Zygaena filipendulae) alongside ubiquitous meadow browns (Maniola jurtina) and gatekeepers make a rich community in this unassuming nature reserve of subtle colours.