Curlew Moon. Mary Colwell

but steady. Under their soft feathers, they are warm and surprisingly fragile. We look each other in the eye and I fancy there is a connection. I stop short of giving each one a soft kiss on the head – that is way too infra dig in front of the Highland Ringing Group.

      By mid-morning each bird has been released into the bright sunshine and the cold, fresh air. As they fly away I wish them well and hope they come back in the autumn so that the geolocators can be retrieved and reveal their secrets. The curlews call out their characteristic ‘curlee’ as they wheel down the beach. I worry that the exploding net and human handling might have traumatised them, but, reassuringly, after some indignant shaking, each one starts feeding. By the time we have packed up, the beach is once again calm, as though nothing has happened. Months of waiting now lie ahead before the birds return in the autumn and the cannon nets are laid out again.

      Cannon netting might seem dramatic but it is a useful tool for birds like curlews that are hard to catch in any other way; and its use is spreading. Two weeks later, at the end of February, I find myself once again stumbling through woodland in semi-darkness. This time it was to find out more about a new inland cannon netting project in the Yorkshire Dales.

      It is late afternoon and I am following (or trying to follow) a silent, stealthy, ex-army officer who barely cracks a twig as he moves through the shadows with ease. His training with the Irish Guards, and a Military Cross for bravery in Iraq, are obviously useful for birding. He floats over the ground and uses the tree trunks as cover. I, on the other hand, fall over every root, get snared on brambles and catch my rucksack on most overhead branches. I can barely see a thing.

      Tom Orde-Powlett is in his late thirties, and retired from the army to help run the family business, which happens to involve the upkeep of a medieval castle and a 6000-acre grouse moor. For six centuries his ancestors have owned and managed Bolton Castle Estate. He also has four small children, so life is busy. Tom, though, is fired with a passion for birds and is involved in all kinds of ringing and monitoring projects around the area. I will return to the grouse moor later in the year, but this visit is to see the large number of curlews that winter in the fields along the River Ure, which tumbles through the valley below the castle. Most curlews in the UK winter on the coast, but some come inland to places like this in quite large numbers. A few hundred birds are known to spend the winter in Wensleydale, making the most of the rough, wet fields below the hills. This is a stunningly beautiful part of England. On this wintry day, the elongated, smooth moors are dusted with snow and produce stark, white wedges against a pale blue sky. England is a crowded country, but the Yorkshire Dales feel wide open and sparse. There is space to breathe.

      The light is fading fast. The fourteenth-century fortress that once hosted the fugitive Mary Queen of Scots looms above us, dark and brooding. Tom leads the way through the small shelterbelt of conifers to the edge of the field where a hundred or so curlews often roost overnight. There is no cannon netting tonight; this is a reconnaissance trip to check their location. We settle on a log, telescopes ready, and chat quietly. Little is known about these Yorkshire birds. Do they breed on local hills or have they come from far away? Are they a mixture of sexes and ages? One theory suggests curlews that winter inland may be predominantly males, as their shorter bills are more suited to reaching food in wet, soft soil. The females, with their longer bills, are more adept at extracting food from sandy, muddy shores and rocky coasts. No one knows for sure, and so Tom, with the help of local nature groups, is trying to find out. In January, over forty birds had been caught using cannon nets and each bird was given a unique set of coloured bands for identification. While the rings were being fitted the birds were also weighed and measured. The majority were found to be male, supporting the theory that the sexes may separate to some extent in winter. More cannon netting is being planned, but in the meantime it is important to keep a lookout for birds already ringed. Once spring arrives it might be possible to see where they nest, or to hope for reported sightings if they are breeding elsewhere.

      There is something tinglingly magical about woodlands, even small patches like this, in the half-light of a winter evening. They are steadfast and full of expectation; there is a sense of a change of shift from day to night, from the known, visible world to the realm of covert creatures that move in shadows. After the wet, warm winter the rotting leaves and rich soil give off a primeval, earthy smell. As a cold wind buffets the valley, the trees provide a sense of calm. I feel I am wrapped in a woody blanket.

      A lacework of bare hedges defines the large field ahead. The ground is sodden and an area of standing water in the middle reflects the grey and pink sky. After a short time, the calls of curlews drift in from the distance. They sail overhead, landing by the water, touching down like fighter planes. Their long, pointed wings tilt to kill the lift and slow momentum. Their heads and necks stretch out and downwards, and their long legs, with pointed toes, dangle below. They delicately touch the earth. At first just a few arrive, then they are joined by more and more. They whistle and call to each other and begin to feed in a herd of about eighty birds, moving first one way, then turning and walking back. A brown hare appears in the background, sniffs the cold wind and lopes away. Occasionally, one curlew rises into the air and sings a succession of ascending notes before floating back to the group. They are trying out their mating displays, and seem restless. Something is stirring in the February air; the approaching spring seems to be awakening their instincts.

      Despite the cold, short days, winter is coming to an end. The world is on the cusp of change. Birdsong becomes louder and more musical, more earnest. Buds bulge and green shoots have more vigour. The curlews feel it. Their migration to their summer grounds is about to begin. It will be a staged journey, not a direct flight. Very soon this group in Wensleydale will split up and head to the same breeding grounds they have always gone to. These are birds of routine and faithfulness. They will stop for a few days in the same fields, in fact the same spot in the same fields, calling and displaying, searching each other out, always heading closer to their final nesting place.

      Most of the Wensleydale curlews might not have far to go. It is likely they spread out over the surrounding moors and upland farms. Others, though, could travel hundreds of miles. Previous studies suggest some birds may head to Teesdale before heading out to Scandinavia. This new ringing project will help fill in some of the gaps, and I left Tom with plans to return when the birds are nesting and the valleys and moors are burgeoning with life. I drove back to Bristol with a mind full of wintery new moon birds singing in a grey, flooded field.

      As the seasons shift, so too do the winds around the Earth and the currents in the sea. Movements in air and water bring a fresh energy to a winter-weary world. That energy can bring new life and new generations – but it can also be lethal. Gales, fog, heavy rain and storms can hit just when the birds are on the wing.

      On an unusually foggy, cold night, on 9 March 1911, there was ‘a tremendous night of Curlew cries over Dublin’.2 Thousands of birds of different species – including curlews, thrushes, starlings, robins and skylarks – were ‘streaming over the south and east coasts of Ireland, heading north. They were exhausted and disorientated.’ One man near Waterford recorded, ‘The whole bird creation was astir and the people of the town were kept awake by the shriek of the Curlew, Duck and Snipe hovering over the town.’ A ship’s captain reported ‘millions of birds’ alighting on his ship. ‘Amongst them was a number of curlews.’ Lighthouse keepers told of birds crying and wheeling around the lanterns in the dead of night. A certain Mr Fanning was awoken from his sleep and wrote, ‘Curlew were heard calling continuously over the town of Lismore … the air was full of them. The nights were dark and foggy, and the birds kept hovering over towns where gas-lamps were lighted.’ And in Carlow, ‘the sky was almost obscured by vast numbers of Curlew and Starling … The streets were practically littered in the morning with the bodies of dead birds.’ Another report describes a man out walking at midnight and finding curlews, ‘walking up and down the flat bank at the side of the river, screaming piteously.’ It must have been a tragic and disturbing sight.

      Returning to their breeding grounds from wintering in southern Europe, these poor creatures seem to have been caught out by extreme and unusual weather. Having been held back for longer than normal by intense cold across the continent,