Many rodents such as voles live underground. Marmots live almost exclusively above the tree line as high as 2,700 m (8,858 ft). They hibernate in large groups to provide warmth, and can be found in all areas of the Alps, in large colonies they build beneath the alpine pastures. Golden eagles and bearded vultures are the largest birds to be found in the Alps; they nest high on rocky ledges and can be found at altitudes of 2,400 m (7,874 ft). The most common bird is the alpine chough which can be found scavenging at climber's huts or at the Jungfraujoch, a high altitude tourist destination.