There, the lowland is limited and mountains plunge into the sea in many places. In some locations, birch thickets grow on mountainsides and valley floors, as well as on the grassy islands of Æðey and Vigur, among others. A vast multitude of eiders, puffins and other sea birds nests in these islands. In recent years, Æðey is only occupied by people in summer but the eider colony is exploited both there and in Vigur, where people reside year round. Some locations along the coast are worth visiting to look for long-tailed ducks and goosanders. Harlequin ducks can be found in quite a few places close to streams and rivers. Wrens and ptarmigans and others can be found in birch thickets. Furthermore, several sea eagle pairs nest in Ísafjarðardjúp. Æðey and Vigur are among the best bird watching sites in Ísafjarðardjúp. The marshlands in Vatnsfjörður and on Reykjanes also have a very diverse and rich birdlife.