The most voluminous river in Iceland is River Ölfusá. Around this time of year you can expect to see a lot of ducks and gulls there, some Greylags and Swans and a Gyrfalcon, a Merlin or even a White-tailed Eagle flying above.
Due to spring water a big part of the river never freezes. When creeks and lakes are frozen over, River Ölfusá is the perfect winter habitat for birds. The river flows just outside our window about 50m away from our house.