The Great Wildebeest Migration: A complete guide

Contrary to what many people think, the Great Wildebeest Migration doesn't only take place between July and September. This is when the nail-biting river crossings occur, which the migration is most famous for. Rather, the Great Migration is a year-round, ongoing mass movement of wildlife. Spurred on by the rains in East Africa, millions of wildebeest, zebra and antelope embark on a perilous quest to find good grazing and return to the southern plains of the Serengeti for the annual calving season.

The Great Migration takes place in the Serengeti-Mara ecosystem spanning Tanzania and Kenya. Moving roughly in a clockwise direction, the journey starts after the calving season in the Ndutu region of the Ngorongoro Conservation Area and the southern plains of the Serengeti National Park. The herds then make their way northwards and westwards toward the Grumeti region. After crossing the Grumeti River, they move further north towards Kenya's Maasai Mara National Reserve which borders the Serengeti to the north. They cross several rivers along their journey, the most famous of which is the Mara River. The wildebeest stay in the Mara for a month or two before circling back south and migrating down to the fertile southern plains to give birth. And so their ancient journey begins anew.

Trying to predict the exact timing of the animals' movements is tricky. If you book an East African safari in peak safari season between July and September in the hopes of witnessing one of the world-famous river crossings, there is no guarantee you'll get to see one. Nature is unpredictable and there's no way to accurately forecast exactly where the herds will be, when the rains are going to arrive, or how long they're going to last. The rains may come early one year and late the next.

Even if you do happen to get the timing spot-on and you're perfectly positioned to watch a dramatic river crossing unfold before your eyes, the migration remains unpredictable. Sometimes, the mega herds stay congregated on the river banks for days before attempting a river crossing. Other times, the animals cross the river as soon as they arrive at the water. Nature dances to no one's tune.

For this reason, it's important to factor in as much time on safari as possible if your goal is to witness a river crossing. However, there's more to the Great Migration than river crossings. Calving season is an equally exciting part of this age-old migratory cycle. But the most important thing to know about the Serengeti and Masai Mara is that the resident game is so prolific and the wildlife sightings so rewarding that you can go on safari any time of year, even outside migration season, and still have excellent game viewing.

The Serengeti and Masai Mara's beautiful scenery and thriving wildlife make them incredibly rewarding safari destinations all year round, even outside migration season. That said, if it's a Great Migration safari you're after, here's a general guide of what tends to happen when:

October to December

The start of the short rains in October sends the wildebeest southwards. Driven by the ever-present need to search out fresh grounds for grazing, the wildebeest leave Kenya's Masai Mara and cross into Tanzania's Serengeti. Don't underestimate how rewarding a safari in the Masai Mara can be during the short rains. Dramatic thunderstorms in the afternoons often present spectacular photographic opportunities, migratory birds arrive in droves and the resident wildlife provides ample game-viewing opportunities, without the crowds of peak season.

While you're sure to spot some stragglers in the Mara come December, by then most of the migratory wildebeest are flooding the vast plains of central and eastern Serengeti in large numbers as they journey southwards.

January and February

The Southern Serengeti and Ndutu Region in Tanzania are the best places to be in January and February. It's one of the warmest times of the year with daytime temperatures reaching 30°C, it falls between the short and long rains, and the chances of witnessing some thrilling predator action are extremely good.

That's because it's calving season.

The wildebeest congregate en-mass on the lush green plains of southern Serengeti and the Ndutu region of the Ngorongoro Conservation Area, where 80% of the females in the herd give birth to over 8,000 wildebeest calves every day within the same two- to three-week period. The sudden availability of vulnerable and easy-to-target prey attracts the Serengeti's big cats, roving packs of African wild dogs, resident hyena clans and the occasional opportunistic jackal which provides safari-goers with some spectacular, action-packed game viewing opportunities.

Your best chance of witnessing the birth of a wildebeest calf or spotting a calf that's just a few hours old is usually around noontime when most predators are seeking a respite from the midday sun. This is nature's way of providing newborn calves enough time to learn how to stand on their wobbly legs and gain strength before late afternoon which is when most predators tend to go on the prowl.

March and April

It might take mere minutes for wildebeest newborns to learn to stand but it takes a couple of weeks before the calves are strong enough to join the herds on the next noisy and chaotic leg of their odyssey which usually begins in March or April. If you're not put off by the occasional afternoon rain shower, the best place to see the herds gathering in ever-growing numbers is in the southwest of the Serengeti National Park.

The long rains usually arrive in March or April and drive the herds in a northwesterly direction. Many camps in southern Tanzania close on account of the heavy rainfall which makes the roads slippery and the terrain difficult to navigate, even in a 4x4.

Some safari lodges, however, remain open because April and May are still good times to go on safari. Room rates are lower, visitor numbers drop, and the dramatic thunderclouds and spectacular sunsets are a photographer's dream. The long rains usher in the start of the wildebeest rutting season. This is when wildebeest bulls, fuelled by testosterone, battle one another for the right to mate. These noisy and sometimes surprisingly violent battles for dominance continue well into the month of May.

May and June

As the long rains continue into May, the pace at which the wildebeest are moving begins to pick up now that the calves are older and stronger. Up to 40-kilometer-long (25 miles) columns of wildebeest, zebra and sometimes Thomson's and Grant's gazelles snake their way northwards through the central Serengeti, bringing them closer to their next big challenge; the Grumeti River.

While the Grumeti River can and does provide some nail-biting wildlife drama, viewing opportunities are fewer and the Mara River crossings tend to be more spectacular. The Grumeti River has less water than the Mara River so the wildebeest can cross the river at any number of points which makes it extremely difficult to predict where crossings might take place.

The end of the long rains in June marks the start of peak safari season in Tanzania, and the Seronera, Grumeti Reserve and northern Serengeti see an increase in visitors hoping to catch a glimpse of the migratory herds as they press on northwards. Once again, the timing of the Great Wildebeest Migration is different from year to year and is dependent on the pattern of rainfall. Mobile safari camps move with the herds and are a fantastic option if you want to get as close to the Great Migration as possible.

July and August

The onset of the southern hemisphere winter in July brings sunshine, blue skies and pleasant daytime highs of 26°C to East Africa. Pack some warm clothing, though. While July is Serengeti's driest month, it's also the coolest. Early morning and evening game drives in temperatures that average 14°C or less can be brisk if you're not dressed warmly enough.

Having survived the dangers of the Grumeti River in the northwest of Serengeti National Park, the wildebeest now face their most daunting challenge yet; the treacherous Mara River crossing in the Northern Serengeti, before the herds head into Kenya's Masai Mara.

Witnessing the chaotic frenzy of a Mara River crossing is one of East Africa's most spectacular safari experiences. As thousands of wildebeest and zebra brave the dangerous waters, some fall prey to gigantic Nile crocodiles, some drown in the frantic race to get to the other side of the river and others are snatched by predators lurking on the riverbanks.

Once again, even though the wildebeest have historical crossing areas, trying to accurately predict a river crossing is impossible. In order to maximise the chances of seeing a crossing on your Great Wildebeest Migration safari, we recommend you book accommodation at a safari lodge that is reasonably close to the Mara River. The further away your safari lodge is from an expected crossing point, the more distance you have to cover to reach the crossing point. By the time you arrive at the lookout point, you may discover that other vehicles have already staked out all the prime viewing positions. Keep in mind that safari lodges with quick and easy access to the river book out fast so you'll have to plan your migration safari at least one year in advance.

River crossings often start in late July in northern Tanzania, and continue well into September and sometimes early October in the Mara. July to September is the peak season for migration safaris.

September and October

September sees gigantic herds of wildebeest grazing their way through Kenya's Maasai Mara National Reserve. Come October, when the short rains arrive, they are ready to begin migrating back down into the Serengeti where the cycle begins anew. August and September are extremely busy months in the Mara. The weather is fantastic, there is almost no rainfall and the dry season game viewing conditions make it easy to spot game. And did we mention the river crossings? Be prepared for crowds and premium safari lodge rates.

If you're looking for a more intimate safari experience away from the masses, consider staying at one of the private conservancies that border the Maasai Mara National Reserve. From there, you can make a day trip into the Mara to see the herds and, with some luck, a river crossing, while still enjoying uncrowded game drives back at camp. Another way to avoid the crowds is to visit the Mara outside migration season in October or November during the short rains instead. You may miss the drama of a river crossing but you'll pay less for accommodation and have plenty of phenomenal wildlife sightings all to yourself without the crowds.

It's easy to see why the annual mass migration of millions of wildebeest and scores of zebra on the vast plains of East Africa is often called The Greatest Show on Earth. Even if you've seen wildlife footage of a river crossing, nothing can really prepare you for the full impact of the drama unfolding in the flesh.

The frantic sound of thundering hooves and churning water. The frenzied sight of hoards of wildebeest urgently trying to get to dry land on the other side of the river. The terrifying odds of falling prey to crocodiles lying submerged in the water and big cats lurking in the riverine shrubs waiting for the right moment to strike.

The bittersweet wonder of calving season on the southern plains of the Serengeti and Ndutu region in Tanzania in February is equally dramatic. The sight of newborn wildebeest calves trying to stand on shaky legs. Lions, who face their own harsh struggles to survive, waiting to ambush them.

We've been privileged to witness the one-of-a-kind experience only the Great Wildebeest Migration can offer, and we can safely say that if a Serengeti or Masai Mara migration safari is not on your bucket list, it should be.

Now that you know there's more to the Great Wildebeest Migration than river crossings and that the animals' movements are guided by the rains, where you go and when you go on safari depends on which events you'd like to witness.