The herds concentrate on the short-grass plains around Ndutu and the southern Serengeti, where mineral-rich grasses support lactating mothers. An estimated 400,000 to 500,000 calves are born within a roughly three-week window. This is a survival strategy, not coincidence: the sheer volume of births overwhelms predators, ensuring that most calves survive even as hyena, lion, cheetah, and jackal converge on the area from all directions.

Predator-prey interaction is almost constant during this period. The open plains offer unobstructed visibility, which makes for extraordinary game viewing. Ndutu is the better-known base, but the Kusini Plains further south offer the same calving spectacle with considerably fewer vehicles. Both areas are excellent, and the choice between them often comes down to which camps are available. This is a significantly quieter phase than the northern Serengeti in crossing season.

As the southern plains begin to dry, the herds drift northward in loose, spread-out columns. The movement is gradual rather than dramatic. There are no tightly packed formations or river crossings yet. The Seronera area of the central Serengeti sees increased activity as the herds pass through, and predator density remains high as resident lion prides encounter the moving wildebeest.

Birdlife is strong following the rains. March sits in a transitional window between the calving season and the long rains, and for travellers with flexible dates it can offer good game viewing without the peak-season crowds.

The long rains arrive, and the herds typically hold in the central and western Serengeti where water and grazing are abundant. This is Tanzania’s low season. Visitor numbers drop significantly, some camps close for the season, and access roads can become challenging after sustained rainfall.

For those comfortable with rain interruptions, there are genuine rewards. The landscape is at its greenest and the Serengeti feels vast and unhurried. Calves born in January are now strong enough to keep pace with the herd, and the reduced vehicle traffic changes the feel of the park entirely.

The herds push westward toward the Grumeti River, forming increasingly dense columns as they move. The first significant river crossings of the cycle occur here, though they are smaller and less publicised than the Mara crossings further north. Large Nile crocodiles patrol the Grumeti, and the crossings carry real risk for the wildebeest even at this earlier stage.

The landscape shifts noticeably in the western corridor. Woodland and riverine forest replace the open plains of the south and centre, which changes the character of game drives. Sightings feel more enclosed, more intimate. This is an undervisited phase of the migration, partly because attention tends to focus on the Mara crossings still months away.

The main body of the migration reaches the northern Serengeti and the first Mara River crossings begin, typically from mid-July onwards. Herds mass on the southern bank in enormous numbers, and when they commit to crossing, the spectacle is immediate and dramatic. Wildebeest call constantly, dust columns rise from the gathering herds, and predators position along the banks.

Not every day produces a crossing. The herds are unpredictable and may approach the river and turn back multiple times. This can test the patience of travellers expecting the spectacle to unfold on command. When a crossing does happen, the scale is overwhelming: thousands of animals funnelling into a narrow stretch of water, the noise carrying for kilometres, crocodiles moving beneath the surface.

July and August offer a genuine chance of witnessing crossings with fewer vehicles than later in the season. Kogatende is the established base for this area, but the Lamai Wedge, a triangular section of the park north of the Mara River, is quieter still. Separated from the rest of the Serengeti by the river itself, the Lamai area has limited access and only a handful of camps, which keeps vehicle numbers low even during crossing season. Both Kogatende and Lamai offer strong resident wildlife including large lion prides and leopard along the river margins.

Crossings continue through September and into October, with herds moving back and forth across the Mara River. Some splinter groups push north into Kenya‘s Maasai Mara and remain there for weeks, while others turn back south. The pattern is fluid and varies day to day. The Kogatende area of the northern Serengeti is the primary base for witnessing these crossings on the Tanzanian side.

Crocodile activity is intense during this period. The river itself becomes a focal point for an entire food chain, with vultures, marabou storks, and fish eagles drawn to the aftermath of each crossing. Between the river drama, the surrounding bush country offers consistently good game viewing. The northern Serengeti‘s limited camp capacity means it feels less crowded than the equivalent experience in Kenya’s Maasai Mara.

The short rains trigger the herds’ return southward, drawn back to the mineral-rich grasses of the southern plains. The movement can be rapid once the rains establish. The central Serengeti sees large herds passing through, and the transformation of the landscape is striking. Dry, golden plains turn green almost overnight.

By late December, the cycle is resetting. The herds are back on the southern plains and the calving season is weeks away. Visitor numbers thin out during this period, and there is a particular quality to the Serengeti in late November and December: a sense of renewal, of the ecosystem drawing breath before the intensity of calving begins again.