The million wings of winter

The balding old spruce at the gate seemed to have sprouted new foliage overnight, thickening its silhouette against the sunrise. Then, as I stepped out, the tree flew apart in a great whirr of wings - a flock of fieldfares taking fright into the morning. There were redwings, too, sifting over the hedges, their flanks a bright chestnut in the warm light from the mountain.

This sudden fall of migrant thrushes, early for west Mayo, came well ahead of frosts and hail showers, but "the old people" would have found it a certain omen for a hard winter. In reality, both birds are regular and widespread winter visitors, mingling in the open countryside.

The great variation in their numbers from year to year is only partly in response to weather. Fieldfares have a favourite food in Scandinavia in the bright orange berries of the rowan, or mountain ash. In years with a very heavy crop, a lot of the birds put off their migration until well into winter.

But they move very swiftly in response to cold, first to Britain, then to Ireland as temperatures fall. Irish records of big "falls" of fieldfares are all in mid-winter, when thousand-strong flocks may cross the east coast.

Their main arrival in Ireland is in November, but even in a mild winter fieldfares tend to move across from Britain after Christmas, hoping to find some last berries on the hawthorns. Their single-minded appetite for wild fruit (and windfall apples, when they can find them) can prove a handicap. The smaller blackbird - another thrush - can survive severe cold spells rather better, because it eats more widely, including food put out by people.

For all their nervous watchfulness and sudden decisions to move on, there is a strong and confident poise to fieldfares. It is small surprise to learn that, nesting together in northern woodlands, they give chase to crows with a furious, scolding chatter and even rain droppings on their heads.

In winter, the "chacking" of their flight call is more subdued, but they keep an affecting elegance of colour: crisp, cool greys and browns above, a glowing, ochre bib, a rich embroidery of flecks on breast and flanks - a bird made specially beautiful in the sombre moods of November.

The redwing is smaller and slighter, rather like a small song-thrush, but with streaks, not spots, on its breast and a pale stripe over the eye (the red is under the wing, in the arm-pit). Its high-pitched, sighing flight call while on migration at night is famous for making itself heard, even above the thrum of city traffic.

This is a bird of northern Europe's forests of conifer and birch, but it also has a race in Iceland, darker and more heavily-streaked, and a few of these turn up on our north-west coast in autumn. The huge numbers that reach us in a hard winter, however, are part of the total exodus from Scandinavia.

Eric Simms, a great authority on thrushes, described redwings arriving from the sea on the east coast of Scotland in late October, "pouring like a torrent of dark liquid into the bare canopies of the trees". He gave up trying to count the birds resting along a coastal strip "where every field, hedgerow, copse, wood and tree was alive with redwings perched or feeding. The total . . . was beyond computation or estimate - it was a staggering sight."

A million fieldfares, rather more of redwings - these are working totals for the birds wintering in Ireland and Britain. Such images and figures help to cushion the sad fate of some that do not arrive on schedule. Redwings, in particular, seem drawn to the lanterns of lighthouses on misty nights: they are blown into the glass and killed.

IN the late 1800s, the Irish ornithologist Richard Barrington paid that keepers of lighthouses to keep a long record of such casualties. The 2,000 specimens of legs and wings they sent him helped him compile the first standard work on Irish bird migration - redwings, of course, just one in a long list of species, coming and going.

To lighthouse keepers from Fastnet to Inishtrahull, the birds must have seemed as fated as moths as they fluttered at the light. The ornithologist R. M. Lockley spent an October night at the lighthouse on North Ronaldsay in the Orkneys, scooping up birds with a net to ring and release at dawn. Most were redwings. He told how "the tower of this lighthouse resounded to the thuds of birds hurling themselves at the glazing. A crash, a flutter of feathers in the wind, and a small body dropping to leeward . . . " Today, with all the lights run by robot machinery, who is to see or hear?

Some migrants - vagrants, more accurately - which have settled in Ireland are the cover story of the latest volume of Irish Birds, the annual research journal of BirdWatch Ireland. These are the little egrets, Egretta garzetta, which have expanded across western Europe and along the Atlantic coast of France.

As Patrick Smiddy and Oran O'Sullivan report, up to 10 years ago the egrets occasionally wandered to Ireland but did not stay: they were mostly overshooting spring migrants. Then birds began to be present all year round, and major autumn influxes in the mid-1990s led to wintering populations of almost 60 birds, mostly in sheltered creeks along the south coast. Breeding began in 1997 when no fewer than 12 pairs of egrets nested alongside herons in the Blackwater valley.

Among the excellent photographs in the 1998 Irish Birds is one of the heronsized great white egret, Ardea alba, at a lake in Co Derry - one of only a handful of Irish records after a long gap. There have been further sightings this year, the latest on the Shannon, just south of Athlone, a month ago. Protection of this beautiful bird has brought dramatic increases in parts of continental Europe - and perhaps a further colonist for a warmer Ireland.

Irish Birds is available from BirdWatch Ireland, 8 Longford Place, Monkstown, Co Dublin, price £10, including postage