Serengeti National Park

The endless movement of wildebeest and other migratory animals in the Serengeti ecosystem is dictated by rainfall and availability of water and fresh pastures. The migration follows the same clockwise pattern every year with slight variations depending on the weather.
According to the official Serengeti National Park guide book, the main wildebeest migratory population ranges a region of 25,000sqkm, in the Serengeti ecosystem, of which about two thirds is protected in the Serengeti National Park, Ngorongoro Conservation Area and the Kenya Maasai Mara National Reserve, the rest lying in the adjacent areas bordering the Serengeti including Loliondo Game Controlled Area to the northeast, Maswa Game Reserve to the southwest, and Grumeti Game Reserve and Ikorongo Game Reserve to the northwest, all located in Tanzania. The migration normally stays in Tanzania for at least 9 months, from November to August. Serengeti National Park encompasses the main part of the Serengeti ecosystem.
From December through to April every year, depending on the onset of the short and long rains, the southeastern Serengeti plains and the open woodlands around Lakes Ndutu and Masek are transformed into a busy holding ground for vast herds of migratory animals, in the main the wildebeest, breeding and re-grouping in their hundreds of thousands. Ndutu, which is geographically within the Ngorongoro Conservation Area, forms an important part of the Serengeti ecosystem, especially the open short grass plains which provide calving grounds for the wildebeest in February and March every year.