The Serengeti National Park, Tanzanias largest national park is located about 335 kilometers north-west of Arusha town. Most tourists visiting the world famous national park are fascinated by the annual migration; millions of Wilde Beest, Zebra and Thomsons Gazelles are driven by ancient instinct to migrate to the Maasai Mara in Kenya. The Wilde Beest usually moves through the northern woodlands between June and December every year to feed on the long grass found during this season. During February and March they migrate to the southern plains where the graze is rich in minerals need to rear their young, when the rain stops in May and June the herds are once again forced to migrate to the north-west. Migratory birds including the stork, pallid harrier and peregrine falcon also use the southern plains during the season. The Serengeti is also renowned for its wealth of leopards and lion, the vast reaches of the park helps the black rhino fight extinction and provide a protected breeding ground for the vulnerable cheetah. The Kirawira River with its population of giant Nile crocodiles has made this area very famous worldwide.