Mývatn has a very jagged shore. In the lake itself, there are numerous rocks and islets. Laxá flows out of Mývatn all the way to the Skjálfandi bay where it joins the sea. Recent geological formations, lava and volcanoes, have all put their mark on the environment in this area. Mývatn is one of the largest lakes in Iceland. It is located at an altitude of approximately 280 metres. It is rather shallow and therefore sensitive to temperature and climate variations. Its drainage basin reaches all the way to the highlands in the centre of the country but the waterways are mostly underground. The influx of water into Mývatn is mostly from numerous springs on its eastern shore. Mývatn is rich in nutrients which explains the multitude of midges from which the lake derives its name ("mý" means midge). The vegetation is fairly diverse. Marshland vegetation alternates with grassy shores. There is also quite a considerable amount of birch thicket. Mývatn is noted for its birdlife and it is difficult to find as diverse a nesting site for ducks anywhere else. Both marshland birds as well as heath land species also nest at Mývatn. Arctic terns, black-headed gulls, red-necked phalaropes and various types of wading birds are abundant at Mývatn. Others that are not as common include the great northern diver, loom, slavonian grebe, falcon, merlin and ptarmigan. Two duck species, the harlequin duck and barrow's goldeneye, are common nesting birds at Mývatn and Laxá. Iceland is their only nesting site in Europe. Höfði, Kálfastrandarvogar and Skútustaðir are among the convenient bird watching sites, as well as Laxá and the shores along the river. Along the northern shore of Mývatn, inlets and ponds can be found where there is abundant birdlife with many nesting species.