Guest blog by Matthew Tickner, RSPB Northern Ireland ecologist
One of the sounds that enlivens autumn in Northern Ireland is the noisy communing of brent geese on the coasts. Their calls, playing out around our sea loughs at present, are unlike those of other geese, but are rather difficult to describe: perhaps guttural, perhaps braying or ‘cronking’, possibly trembling, or sometimes described as sounding like a mob of small dogs. This is an easily learnt call, though, and - once known - is guaranteed to become evocative of season and place.
Brents are the most numerous of our wintering geese and are the smallest, being just a little larger than a mallard (though perhaps plumper). Whilst four races or subspecies of brent have been recorded on the island of Ireland, all are rare apart from the light-bellied. Ours has the palest belly and flanks of all, as its name suggests, these underparts contrasting with grey-brown upperparts. The head and neck are blackish, and the latter accommodates a wispy white collar on adult birds.
These birds arrive with us from September onwards, pitching up at our coast from the north in often loose parties that aren’t quite like the tight skeins of most other geese. They are from the East Canadian High Arctic population of light-bellied brent geese (to give them their official title), which breeds in Canada and winters almost entirely in Ireland, with smaller numbers in Britain, the Channel Islands and north coasts of France and Spain.
Spare a thought for the efforts they have expended when you see them making our shores, for they have undertaken one of the longest migrations of any Western Palearctic goose population: perhaps up to 3,000 miles one-way. From their breeding grounds on the barren and boggy Canadian tundra, the family groups will stop at sites on Greenland - traversing its icecap - and Iceland, before crossing the North Atlantic to our shores.
Once they have all arrived, virtually the whole of this population of brent geese winters in Ireland, and sites in Northern Ireland hold the vast proportion of the birds at certain stages of the winter; Strangford Lough is the single most important site for the population outside the breeding season, with Lough Foyle also of major significance.
The population is censused annually, with observer coverage in western Iceland, western Britain, northern France and throughout the island of Ireland in mid-October. Numbers of young are assessed where possible (they can be distinguished by whitish feather fringing on the upperparts), affording information on the success or otherwise of the Arctic breeding season. Currently standing at around 35,000 birds, the population may have had a welcome boost to numbers this autumn, as the signs are that 2019 has been a bumper breeding season.
If you want to see these birds for yourself, perhaps to wonder at their journeying capabilities, or just work out how on earth to describe their calls, then there are superb opportunities to get up close at both Strangford Lough (try WWT’s Castle Espie Wetland Centre) and Lough Foyle (try RSPB’s Lough Foyle reserve at Ballykelly). Visiting a couple of hours either side of high tide means birds will be closer to the shore and thus easier to see.
Photos by Matthew Tickner