It may weigh just over a kilogram, but the light-bellied brent goose is one of the planet’s toughest birds.
Every year they fly nearly 3,000 miles in a death-defying journey spanning two continents.
But this year — for the first time in nearly half-a-century — the small black birds have made the journey sooner than normal.
Since August 30 the geese have been descending on Co Down’s Strangford Lough in their thousands.
More than 5,000 brent geese are now grazing along the lough, feasting on its vast expanses of eel grass.
Their arrival is premature by two weeks, a phenomenon which has not been seen since records began here in the mid-1960s
The early arrival is unusual and likely caused by strong tail winds which carried them on from Greenland to Strangford Lough bypassing their normal stopover in Iceland.
Some birds have even continued past Strangford Lough to Dublin, to the west of Ireland and even Devon.
Every autumn 90% of the world’s population of light-bellied brent geese come to Strangford Lough to restore their energy levels after their annual trek through some of the world’s most hostile climes.
The 2,900-mile journey is the longest, and one of the most dangerous, migrations made by any of the geese species.
The usual journey takes the brent geese from their summer breeding grounds in Canada to Iceland, where they rest and feed just west of the island’s capital Reykjavik, before heading on to Ireland. The hardy geese run the gauntlet of predators, including man, as subsistence hunting is still common in the Arctic.
But this year thousands of the geese cut the arduous journey short by a fortnight.
Time will tell just how many made the trip successfuly as the birds already here are joined by more flocks until numbers peak in mid-October.
John McCullough, learning manager at WWT Castle Espie Wetland Centre, said: “If the birds find favourable weather conditions to speed up their hazardous journey, they would be foolish not to use it.
“The early arrival of geese could mean that they have had a favourable summer in the Arctic and have reached migration condition early.”
The population of young light-bellied brent geese has see-sawed. An increase of just over 1% in young brents in 2010 was followed by a 25% boost the following year.
Brent numbers normally increase gradually from early September to a peak in mid October.
In 2011 a record 38,000 were counted before they dispersed to other bays and estuaries around Ireland with several hundred making it as far as northern France.
Breeding success is never guaranteed however, and with cold arctic summers, repeated years of poor breeding can quickly take their toll.
Brents are a small, dark goose — the same size as a mallard duck.
It has a black head and neck and grey-brown back, with either a pale or dark belly, depending on the race.
Adults have a small white neck patch. It flies in loose flocks along the coast, rather than in tight skeins like grey geese.
It is an Amber List species because of the important numbers found at just a few sites.