it.wikipedia.org/wiki/Masai_Mara
Blue wildebeest are the dominant inhabitants of the Maasai Mara.[2] Around July of each year, these animals migrate north from the Serengeti plains in search of fresh pasture, and return to the south around October. The Great Migration is one of the most impressive natural events worldwide.[3] It involves some 1,300,000 blue wildebeest, 500000 Thomson's gazelles, 97000 topi, 18000 common elands, and 200000 Grant's zebras.[8]