On 23rd April, a flock of about 80 Light-bellied Brent Geese fed on the shore in front of Loch Gorm House and I was able to read the letters on the leg rings that one bird was wearing. It had the letter 'N' on its right leg and 'J' on its left. I have now had the details of when and where it was ringed and other sightings of it.
26th October 2003 Caught and ringed, Strangford Lough, SE of Belfast. It was a juvenile, hatched in 2003.
Winter 2003-2004 Seen frequently at Strangford Lough, up to mid-February
Winter 2004-2005 Returned to Strangford Lough on 4th October and seen regularly until mid-April
Winter 2005-2006 Seen Strangford Lough on 5th October and many times thereafter to February
29th April 2006 Seen on the west coast of Iceland, and again on 3rd May
Winter 2006-2007 No sightings
Winter 2007-2008 No sightings
Winter 2008-2009 Seen Cork Harbour, on the south coast of Ireland on 25 December
Winter 2009-2010 Seen Wexford Harbour, on the south-east coast of Ireland on 5 April
Winter 2010-2011 Seen Strangford Lough four times in November
23rd April 2011 Seen at Bruichladdich, Loch Indaal
26th April 2011 Seen at Durness, Sutherland
So, after wintering regularly at Strangford Lough for a few years, it seems to have gone somewhere else in more recent winters. This will be somewhere in Ireland, but presumably where there are fewer observers. To be seen twice in Scotland on the same spring migration is unusual.
These Brent Geese breed in arctic Canada and all winter in Ireland. They make a 2,500 mile (c.4,000 km) migration twice a year, so the bird I saw, which will now be back in Canada having made its 16th journey, has travelled a minimum of 40,000 miles not counting all the shorter journeys it will have made in Ireland.
There's a lot more here: http://www.irishbrentgoose.org/
Here's a photo of some Brent on the Bruichladdich shore that I took a couple of years ago.