Cord Fochno, is a raised mire; a great lens of peat next to the Dyfi estuary a few miles to the north of Aberystwyth. At its heart, there is no solid ground, just layers of compressed Sphagnum mosses laid down on a freshwater wetland since the end of the last Ice Age. In the past, the peat was cut for fuel and the land enclosed and drained for agriculture; the mire is a remnant of the former ‘waste’; some edges are now being restored by building bunds and retaining water within the old diggings.

It is a hydrologically isolated ecosystem that is nutrient poor and acidic because the only inputs into the shallow dome of peat are from rainfall; a great ombrotrophic, literally cloud-fed, dome that draws the water table up to the surface. So it is comprised of restricted-range plants and associated invertebrates that specialise in waterlogged, low nitrogen environments. It is also physically isolated; the only access is a circular boardwalk but this hardly makes a dent on the map.

On the seaward edge of Cors Fochno, is a popular tourist destination with ribbons of static caravans and swarms of beachgoers. Borth is a long, narrow street of a village next to the sea and lined with painted Victorian terraces; these, together with a red brick railway station and smattering of farmhouses, clubhouse and other buildings rudely interrupt the wide horizon. Cors Fochno is better known to most tourists as Borth Bog; it sounds more of a public convenience than one of the rarest and most threatened habitats in Europe.

On the edge of the raised mire, a nest of nightjars is hidden in impassable, leggy heather amidst deep green birches. Two young are ringed by Tony Cross and assistant Ed O’Connor and replaced in the bare, black ground that makes the rudimentary nest. There are more than a dozen pairs of these moth-eating, summer migrants on Cors Fochno.

In a nearby field, Highland cattle graze, half-hidden in the long grass; these are deployed to help manage the wet grasslands that fringe the mire; they stodge about, grazing the sward and their heavyweight battering breaks up the ground and creates muddy patches, pools and tussocks, attractive to a wide range of species such as breeding waders.

The Afon Leri is a tidal river that runs straight as an arrow down a diversionary cut on the seaward edge of Cors Fochno and divides the mire from coastal reedbeds and grasslands. Further west, the railway marks the division between reedbed and golf course and then the coast road marks the boundary between golf course and the beach and sand dunes at Ynyslas. The raised mire is thus wreathed in layers of protective habitats and is a low-lying, distant and somewhat mysterious wilderness when viewed from the coast.

The Leri is often full of mullet and on this leaden evening in late July is hunted by an osprey, perhaps one of the pair from the nearby nest in the Dyfi estuary. The adjacent reedbed holds hordes of sedge warblers fattening up on plum-reed aphids before making the giant leap south to tropical Africa; many are caught in a mist net as they move through the reeds. At dusk, swallows suddenly rush in to roost in the reeds and more than a hundred are caught in other mist-nets and quickly ringed before dusk ends. The numbered metal rings patiently applied to thousands of migrating birds over the past decades have provided intimate and important data on movements and survival that tell a story of the inseparable ecological link between Europe and Africa.