After a few days at the mainland I was back in Longyearbyen again, and through the telephone I found that there was a Gadwall (Snadderand) in the valley. I met up with a friend on the plane who was more than happy to join in re-finding this bird again. On our way out we first encountered a flock of Brent Geese (Ringgås) at Tuedammene. In amongst the regular ssp. hrota were one ssp. bernicla. This subspecies is supposed to be in Siberia, but it is apparently not an entirely uncommon sight in these parts of the Arctic. I have uploaded a picture of it together with two ssp. hrota.
The Gadwall was not difficult to find, and it was swimming alongside a male Wigeon (Brunnakke). I have uploaded a record-shot of the bird here.