Where wild geese fly

ANOTHER LIFE: In the High Arctic, summer is already fading. The sun sets at night and the temperature dips to freezing; a brief skin of ice glazes the mossy tundra pools and stills the moulted goose feathers drifting at their rims. On low island coasts at the north-east of Canada, at the edge of the polar sea, thousands of light-bellied Brent geese from Ireland feel the first stirrings of the need to fly south.

For just four of these geese (sturdy ganders, in fact) the move into flight will be tracked by radio signals, beamed to a satellite from tiny transmitters fixed to their backs. A map displayed on a website (www.wwt.org.uk/brent) will begin to change: four dots will shift, day by day, as Kerry heads off from Bathurst Island, Austin from Ellesmere, Hugh from Amund Ringnes, Major Ruttledge from Elles Ringnes.

The dots will skim the Greenland ice-cap and pause for a while in western Iceland, then move on and converge, in early September, on mud-banks at the northern end of Strangford Lough, Co Down.

This, at least, is the hopeful scenario of the Wildfowl and Wetlands Trust (WWT), whose education centre at Castle Espie overlooks the lough.

Strangford is the autumn hub of a good three-quarters of the Irish population of Branta bernicla hrota - almost 21,000 birds gathered there last year, the highest total in 40 years.

The light-bellied Brent is a race, or sub-species, of the Brent goose, of which another, separate population migrates between Arctic islands north of Europe, such as Svalbard, and the north-east of England. The vastly more numerous dark-bellied race, Branta bernicla bernicla, has up to 300,000 birds and breeds in Siberia and winters in England and France.

Among Ireland's goose species, however, the Brent's migration is certainly the most energetic, taking it far past the nests of the barnacle goose on the cliffs of north-east Greenland and even beyond the breeding grounds of our white-fronted geese in north-west Greenland. It is also, as it happens, the most abundant and accessible of our geese. While the Greenland white-fronts keep to remote bogs on their way to the sanctuary of the Wexford Slobs, and barnacles gather in nervous flocks on coastal fields and grassy islands of Co Mayo and Co Sligo, the Brents spread out to bays and estuaries around most of Ireland.

The very first to arrive, indeed, are parties of non-breeding birds that touch down in Tralee bay at the end of August. As autumn wears on, small parties of Brent move about widely between the western bays, but the biggest winter flocks disperse from Strangford to haunt the east coast estuaries.

Hundreds arrive on the North Bull in Dublin bay, to feed just over the sea-wall from city houses and the DART.

For the WWT, however, this small and stocky marine goose is the prize visitor to its centre near Comber on the western shore of Strangford, with its hides and coffee shop and the largest collection of ducks, geese and swans in this island. The satellite tracking project confirms Castle Espie's special focus on a bird whose welfare has sometimes seemed rather taken for granted.

Like most species breeding in the High Arctic, Brent are prone to big swings in population, with freezing summers and predator attacks a year-to-year hazard. In the coldest Arctic summers, when average temperatures for June stay below -3 degrees C, the geese do not attempt to nest.

And in some years, when Arctic foxes are especially abundant, their predation on the young geese can wreck the whole breeding season.

Even their Irish winter refuge has had its natural disaster. In the 1930s, for example, the beds of marine eel-grass, or Zostera, in Strangford and many other estuaries died back through a wasting disease. The birds take their first weeks of nourishment from the plant when they arrive in autumn, and its failure hit them hard; within 20 years their numbers at the lough were down to a few hundred.

Only as Zostera recovered, and shooting was banned from 1960, did the island's flock begin to build again. After a lean period towards the end of the 1970s, the population built to a peak of around 24,000 before dropping back to a more stable number.

The first research into summer breeding was begun in the late 1960s by the Canadian Wildlife Service, but the 1980s also drew young Irish ornithologists from UCD to follow the geese over Polar Bear Pass on Bathurst Island and ring 557 of them with large yellow leg-bands. Some of these birds, observed in their Irish winters, helped to map the movement of geese between the main feeding-sites - even, as it turned out, between Strangford and the Kerry bays.

The six geese originally "wired" for the present project were caught and fitted with transmitters during the Irish birds' stopover in western Iceland in May (of the two that came to grief, Oscar was found dead by Icelandic children collecting eiderdown, and Arnthor went silent somewhere over Greenland - victim, perhaps, of a gyrfalcon strike).

The project may add little to the facts about where the Irish Brents breed, but knowledge of their exact migration route and staging posts will help in international conservation strategies. And even though hunting of Brent geese has been banned in Ireland for nearly 50 years, other threats remain.

Despite the rich wildlife that has made Strangford Lough an obvious choice for every kind of conservation designation, the WWT complains of the lack of zoning strategy or proper management plan. Autumn hunting too close to the Brents' feeding sites, dog-walking, horse-riding, jet-skis and low-flying aircraft are some of the disturbances it cites.

There is now, however, an information network, based at the Strangford Lough Office in Portaferry (tel: 028-4272-8886), which may lead to more fruitful liaisons. It has just produced an excellent booklet, Out and About around Strangford Lough, which deals well with the natural fabric of the lough and where to go to explore it.