Where is the Great Migration month by month?
The Great Migration follows the rain, not a calendar: only the calving from January to March in the Ndutu region in the south is fixed; the herds are in the north on the Mara River, usually from July to October. This article shows where the herds are at any given time and why even the Mara crossings are not guaranteed.
What the Great Migration is
The Great Migration is the annual migration of wildebeest, zebras and gazelles through the Serengeti ecosystem in East Africa. It crosses national borders. In Tanzania it includes the Serengeti, the Ngorongoro Conservation Area, Maswa, Grumeti-Ikorongo and Loliondo; in Kenya, the Masai Mara. The circular route covers around 800 km, and individual animals travel up to around 2,500 km in the course of a year.
The driver of the migration is fresh, nutrient-rich grass after rain. The rainy season in the Serengeti ecosystem lasts from November to May, peaking from March to May. The dry season runs from June to October. Where it has rained, forage grows, and that is where the herds move. The migration therefore follows the weather, not a calendar.
How many animals migrate
How many wildebeest are on the move is unresolved as of October 2026. The Tanzanian Wildlife Research Institute TAWIRI carried out the 25th aerial census in the Serengeti ecosystem from 28 to 31 March 2023. The result, according to the TAWIRI report: around 1,366,109 migrating wildebeest, with a standard error (statistical uncertainty) of ± 231,741. The censuses are carried out every two to three years.
A satellite study published in 2025 (Duporge et al.) analyses images using artificial intelligence and arrives at around 500,000 to 600,000 wildebeest for 2022/2023. Why the aerial census and the satellite count are so far apart has not yet been scientifically resolved.
The wildebeest are accompanied by around 200,000 to 250,000 zebras, depending on the survey. In addition, there are around 400,000 gazelles, which were not separately counted in 2023.
For context: in 1955 the wildebeest population stood at around 190,000 animals. After the rinderpest vaccination of livestock from 1958, it rose and has been above one million since the mid-1970s. In TAWIRI’s assessment, predation (being hunted by predators) is secondary in the development of the population. Rain and forage, land-use change and poaching are more decisive.
The herds through the year
| Period | Where the herds are mostly found | What you see |
|---|---|---|
Ndutu region in the south of the Serengeti, fresh grass after the rain | ||
Transition phase: the herds leave the south and disperse | ||
Heading north via the Western Corridor and the central Serengeti, depending on the rain | ||
North of the Serengeti, Mara River area | ||
Return to the south with the first rains |
The calving takes place from January to March in the Ndutu region in the south. The national parks authority TANAPA names the dry season from June to October as the best time to see the migration, without assigning the months to any region; the herds are in the north on the Mara River, usually from July to October. There are no fixed months for the western corridor along the Grumeti River and the central Serengeti. There, the herds move between the two poles of the migration; exactly when depends on the rainfall of the given year. With a focus on the Western Corridor, the trip 11-Day Great Migration Western Serengeti goes wherever the herds are at the time.
The timing and location of the movements vary from year to year, depending on rain, drought and human influence. The table therefore shows the typical pattern, not a timetable.
The calving season in the south
Based on the experience of the Wildfinder team in Arusha, the calving season runs from January to March, and the first herds arrive as early as December. Within a window of around 3 weeks, almost 500,000 calves are born. It happens in the Ndutu region in the south of the Serengeti, where the grass is particularly nutrient-rich after the rain; the region lies in the neighbouring Ngorongoro Conservation Area, which is part of the Serengeti ecosystem.
Calving in a short, concentrated window is a survival strategy. Lions and hyenas are the most important predators of the wildebeest. Because almost all the calves are born at the same time, the predators can only catch a fraction of them. The success rate of individual attacks drops.
If you are planning a trip, this means: from January to March the herds are densely packed in the Ndutu region in the south, and predators are correspondingly active. The first herds arrive as early as December, so the best time to visit Ndutu is December to March. If you want to see newborn wildebeest, January to March offers the best chance of the year. The trip 11-Day Great Migration Southern Serengeti combines Tarangire and the Ngorongoro Crater with days between Ndutu and the southern Serengeti during the calving season.
The Mara River crossings
In the dry season, the herds reach the north of the Serengeti. This is where the Mara River lies, the best-known obstacle of the migration route. Crocodiles wait at the crossings.
Long-term data from the Mara Project show how dangerous the river is: between 2001 and 2015, mass drownings occurred in at least 13 out of 15 years, an average of around 6,250 dead wildebeest per year. The carcasses are also part of the ecosystem, as they feed nutrients into the river itself.
Even more important for your planning: fewer and fewer wildebeest cross the river at all. GPS data from 1999 to 2023 show that, in the past, practically all collared wildebeest (marked with GPS transmitters) crossed the Mara River. In more recent years the figure was sometimes below 50%, and in 2021 only 17% (5 of 28 animals). The Serengeti Biodiversity Program cites dry conditions in the Mara Triangle and in Lamai, as well as increased tourism pressure, as possible causes. Between 1999 and 2019, the wildebeest also increasingly avoided areas with a lot of tourist infrastructure, including Seronera, Kogatende, Lamai and the Masai Mara, and spent more time in Grumeti, Ikorongo and the southern plains. This shift is ongoing research, not an established new rule.
So even in the dry season, a crossing is never guaranteed. You can improve your chances with the right time window and the right region, but there is no certainty. In the north at the Mara River, the trip 11-Day Great Migration Northern Serengeti follows a route that is planned around the position of the herds, not the calendar.
What this means for your travel planning
Plan around the phase you want to see, not a fixed calendar.
See the calving
- Travel season: December to March, calving from January to March
- Region: Ndutu region in the south of the Serengeti
- You will see large herds, newborn calves and active predators
See the river crossings
- Best time to go: dry season, July to October
- Region: north of the Serengeti on the Mara River
- Crossings require patience and are not guaranteed
Everything about the weather, the rainy seasons and the question of which month suits your trip is covered in the article on the best time to visit Tanzania.
On a private safari with Wildfinder Safaris, you travel in a private vehicle with a personal guide from the team in Arusha, on your own route. The team sets the duration and parks after your enquiry, tailored to the part of the migration you want to see.
Frequently asked questions about the Great Migration
When is the best time to see the Great Migration?
That depends on what you want to see: the calving from January to March in the Ndutu region in the south, where the first herds arrive as early as December, or the river crossings in the north usually from July to October. There is no fixed calendar; the migration follows the rain.
How many wildebeest migrate in the Serengeti?
That is disputed as of October 2026. The 2023 TAWIRI aerial count arrives at around 1,366,109 migrating wildebeest, while an AI-supported satellite study from 2025 arrives at around 500,000 to 600,000. In addition, around 200,000 to 250,000 zebras and around 400,000 gazelles migrate.
When is the wildebeest calving season?
Based on the experience of the Wildfinder team in Arusha, the wildebeest calve from January to March in the Ndutu region in the south of the Serengeti. Within a window of around 3 weeks, almost 500,000 calves are born, in the south of the Serengeti.
Are the river crossings on the Mara guaranteed?
No. The timing and location vary from year to year, and in the long term fewer and fewer wildebeest cross the river: in 2021 it was only 17% of the collared animals. Even in the dry season you need patience.
Do the wildebeest travel as far as Kenya during the migration?
Yes. The migration crosses the border between the Serengeti ecosystem in Tanzania and the Masai Mara in Kenya. There is no reliable figure for how many animals cross the border each year.
- TAWIRI: Aerial Point Survey of Wildebeest in the Greater Serengeti Ecosystem, Wet Season 2023
- Serengeti Biodiversity Program: Annual Report 2023–2024 (TAWIRI, TANAPA, Frankfurt Zoological Society)
- TANAPA: Serengeti National Park
- WWF Tanzania and TAWIRI: Serengeti-Mara Wildebeest Migration at a Crossroads (conference paper, December 2025)
- Journal of Animal Ecology: Mduma, Sinclair, Hilborn (1999), Food regulates the Serengeti wildebeest
- Yale Mara Project: Wildebeest Mass Drownings (Subalusky et al. 2017, PNAS)
- Africa Geographic: Wildebeest migration woes, AI counts indicate low numbers (Duporge et al. 2025)
