An aqueous gem amid mountains and lava fields, Lake Mývatn is fed by cold springs in the lake bottom and warm springs in the northeastern corner. The shallow lake—37 square km (14 square mi) in area yet averages only 8 feet deep—teems with fish, birds, and insects, including the swarming midges for which the lake is named. These tiny flies are essential in the bird food chain.
Waterfowl migrate long distances to breed at Mývatn, 115 species of bird have been spotted in the area, including 28 duck species. Indeed, the lake has Europe's greatest variety of nesting ducks, including some—the Harlequin duck and Barrow's goldeneye—found nowhere else in Europe. Dozens of other kinds of waders, upland birds, and birds of prey also nest here. Be sure to stay on established trails and pathways, as nests can be anywhere. During summer you might find a head net useful to protect yourself against the huge midge swarms.