7 Days Western corridor Wildebeest Migration Safari will take you to a part of the Serengeti known as the Western Corridor. The main feature of this area is the two Rivers: the Grumeti and the Mbalageti. This area sustains a very good permanent wildlife population, including all the predators, zebra, and wildebeest. There is also a wide variety of birdlife. The migration passes roughly between May and July, pausing to gather momentum before crossing the crocodile-rich waters of the Grumeti River.