At the heart of the Serengeti ecosystem lies an ancient phenomenon that is the largest movement of wildlife on earth. In pursuit of food and water, over one and a half million wildebeest and half a million zebra and antelope migrate north from the Serengeti to the adjoining Masai Mara reserve in Kenya every year. It is rated as one of the world's most spectacular natural events - every year over a million wildebeest, zebra and antelope migrate clockwise around the Serengeti-Masai Mara ecosystem, taking in two different countries and making time for birthing, courting and mating on the way.
But the trouble with the Wildebeest Migration is that if you get your timing wrong, you will end up gazing out over a wildebeest-less savannah and wondering where all the animals went. You need to work out where to go and when. Based on historical data, this guide is not infallible (changing rainfall patterns make predicting the Migration an inexact science) but it will give you an idea of where the herds are likely to be.
Southern Serengeti: From December to March, the herds are in Tanzania's Serengeti, moving south from the north-east region and into the southern Serengeti. Ndutu area and Ngorongoro Conservation area - which often means out of the confines of the (unfenced) national park itself. It is calving season - prepare yourself for lots of wobbly babies... and lots of heartbreak as predators swoop in. Predatory leopards, hyenas, cheetahs, jackals and lions eat their fill. You can follow the wildebeest at Kusini, Ndutu and Maswa. On these rich grasslands, the gnus produce 8000 calves a day for a three week era.
West Serengeti: On a Serengeti West Safari around the end of April, May and June, a vast army of blue wildebeests along with its herbivore partner, zebras, mill around the Western Corridor, south of the Grumeti River, some harassed behind by lions and ahead by giant Nile crocodiles.
Central Serengeti: Your Serengeti Central Safari in the Seronera Valley offers a year-round game-viewing with impressive populations of bovids, terrestrial predators, reptiles, amphibians and birds, which remain even after the spectacular hordes of blue wildebeests and zebras have gone.
North Serengeti: From July, August to September, the Mara River in northern Serengeti affords the most dramatic river crossings. Fierce and deep, cliff-sided and rain-swollen, the river takes an enormous toll of the exhausted and terrified wild cattle that surge through its torrential flow. Be advised that catching a crossing is unpredictable as the timing and duration depend on rains and dry season. Where there has been little rain, few wildebeest actually cross the Mara River into Kenya.
On September, the herds break up into smaller groups - about half of the animals remain in the northern Serengeti, the rest are swapping stories in the Masai Mara ('Did you hear that Nigel didn't make it across the Grumeti?').
East Serengeti: Enjoy a Serengeti East Safari during October and November when the mega herds return from Masai Mara in Kenya to the rich plains of the Serengeti National Park, east of the Grumeti River, passing through Lobo and Western Loliondo and under the majestic Gol mountains. Your best bet is not the Masai Mara because it is a smaller reserve than the Serengeti and there may be a lot of other visitors. The conservancies in the Mara (Serengeti) are much less crowded and, not only will you still be able to witness the Migration, but you will also be benefitting the Maasai communities who have lived there for thousands of years.