Now with birds already in Iceland, numbers building there and falling here (and some passage and short-term stopover en route north through Ireland and W Scotland) weather will play a key role in determining the speed of the migration to SW Iceland.
Information on how this journey is conducted is limited to just a few satellite-tracked birds now about a decade ago. Birds from Co. Kerry (n=2) migrated via the west coast (Inner Galway Bay) and birds tracked from Wexford headed up the east coast, staging at Dundalk, Carlingford and Strangford for up to around 1 week.
Our most detailed series of tracks show a bird leaving Wexford on 16th April in SE winds, stopping at Dundalk (< 1d), Carlingford (2d) and Strangford (5d) - a total of ca. 7 days - and then making the flight at nightfall on 23rd April. Within 24 hours the bird was at Alftanes in SW Iceland but it had made landfall by 18:00 (about 20 hours after departure) taking a route E of Rathlin Island and to the west of the Outer Hebrides. That bird was in fact seen at Castle Espie and at Alftanes at either end of the journey!
That individual staged in W Iceland until 30th May and as this season progresses we'll describe the stages of the journey to give a flavor of the timings and routes that the birds of 2016 will be experiencing.