The Red-necked Grebe is a waterbird that lives in temperate areas in the Northern hemisphere. It a rare vagrant in Iceland. It breeds in fresh water lakes but winters by the coast or in estuaries. This Red-necked Grebe was in the harbour at Þorlákshöfn in March. It is in its winter plumage which is less colourful than in summer.
See: https://www.allaboutbirds.org/guide/Red-necked_Grebe/id#
The Long-Tailed Duck is a noticable duck because of its beautiful colours and long tail. Global warming is probably a threat to its existence. It is on the IUCN Red List of Threatened Species, with the status vulnerable. In the wintertime it stays in the ocean around Iceland but in the summer it is a breeding bird in the interior where the climate is colder, more arctic.
This picture is taken in Veiðivötn, Fishing Lakes, in the interior of Iceland. The male bird is at the front, the female behind.