RICHARD WILLIAMSON Nature Trails...All eyes on the skies awaiting the swallows' return to our shores

I have watched swallows arrive on the coast of Cyprus, a ripple of blue as continual as the wavelets across that vast plain of ultramarine. Swallow and sea seemed to merge as one. How glad we were to watch them descend hungrily on the swarms of flies around the cookhouse of our RAF camp.

We could hear the snap of their beaks around the cooking pots. They hovered inside the smelly marquees as we ate stewed mutton and ate our iron rations of wine gums and tinned butter.

They fed for a week with us on Cape Greco near Famagusta. They diverted thoughts of EOKA terrorists and the ambushcades they made with buried mines and machine gun crossfire when the landrovers were stopped in their tracks.

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Then the swallows left us, and carried our thoughts to winding rivers like the Arun or the Bure, the peaceful green meadows and Easter peals of bells in Shires.

I have seen this mesmeric illusion of swallows and sea interweaving in a weft and warp of wave and wing down in Portugal. It happens on these curious inland seas they call Lagoas where the Atlantic forces entry through the dunes and storms into the land with waves cresting like white horses.

Shoals of fish tumble gladly in upon this tide, feeding on the nymphs and seaweed, not realising they will never get out again. The local fishermen stand patiently like herons around the shore.

Lovely though the southern lands may be, the tide of swallows will swing you on in spring. So here we are in England waiting patiently for their arrival. Their isochronal lines across the breadth of Europe follow the isotherm of 9 degrees C. Or so it did 50 years ago.

With less swallows these days their flock urge is not so great. Huge flocks of birds give spontaneous action. But global warming has moved that synchronous thermline north as well. In Sussex the usual date for arrival is March 10.

Safe in our Sussex bubble, far from trouble of the Syrian sort, we watch the swallows. Still so much to see in them.

We could be like Dorothy Wordsworth, safe from Napoleon and his wars two centuries ago, as she watched the swallows flying around restlessly, flinging their shadows on the sunbright walls, interchanging and crossing each other, expanding and shrinking, appearing and disappearing together, the mesmerism of shapes changing, wondering what was real and what was an illusion.

How vital these things are to our wellbeing, these havens of memory and madeleine. Or are they? Perhaps children today hardly know what swallows are any more.

Do they see them? Or will they live one day in a background of text messages, and the weft and warp of electronic patterns in a digital maze with nature seen only distantly in the download time?