The Savuti Marsh area is 10,878 km2 (4,200 sq mi) large, constitutes the western stretch of the Chobe National Park (50 km (31 mi) north of Mababe Gate). The Savuti Marsh is the relic of a large inland lake whose water supply was cut a long time ago by tectonic movements. Nowadays the marsh is fed by the erratic Savuti Channel, which dries up for long periods then curiously flows again, a consequence of tectonic activity in the area. It is currently flowing again and in January 2010 reached Savuti Marsh for the first time since 1982. As a result of this variable flow, there are hundred of dead trees along the channel's bank. The region is also covered with extensive savannahs and rolling grasslands, which makes wildlife particularly dynamic in this section of the park. At dry seasons, tourists going on safari often view the rhinoceros, warthog, kudu, impala, zebra, wildebeest and a herd of African bush elephants. At rain seasons, the rich birdlife of the park (450 species in the whole park) is well represented. Packs of lions, hyenas, zebras or more rarely Southern African cheetahs are visible as well. This region is reputed for its annual migration of zebras and predators.