The great wildebeest migration is one of the world’s largest mammal migrations with an estimated 1.8 million hooved mammals including 1.3 m wildebeests, 200,000 plains zebras, 200,000 Thomson’s gazelles (Eudorcas thomsonii), and 15,000 Elands (Taurotragus oryx). The animals migrate in search of fresh pasture and water following ancient clock-wise migratory routes across the trans-border Serengeti-Mara Ecosystem in East Africa. The ecosystem stretches for over 40,000 sq. km connecting Serengeti national park in northern Tanzania with Maasai Mara national reserve in western Kenya. The protected areas interconnected by a series of wildlife corridors including Ndutu Plains part of Ngorongoro Conservation Area. Among other wildlife managment areas and private game reserves adjacent to the main protected areas serve as buffer zones to balance tourism growth with environmental conservation and local community well-being.
Mega Herds and Splinter Groups
The wildebeest migration is highly dynamic in nature. The animals tend to scatter across into several mega herds and splinter groups each moving at its own pace. This is due to natural events shaping the migration such as calving and breeding seasons, river crossings, and intensity of predation. The diverse grazing and routing patterns means that there are a variety of different locations from which to witness the migration.
The Great Wildebeest Migration Calendar – Month by Month Guide
January to March – Calving Season
The months of January, Febuary and March are considered as the calving season. The herds are mainly in the Southern Serengeti sector. Some are scattered in the Ndutu Plains part of Ngorongoro Conservation Area.
April to June – Rutting Season
The rut or mating season happens between May and June in the Western Corridor of Serengeti national park. The animals cross the Grumeti river moving into northern serengeti.
July to October – Mara River Crossings
The wildebeests attempt to cross the Mara river from northern Serengeti into Kenya’s Maasai Mara national reserve. When in Maasai Mara, the herds spread for grazing around Musiara Marsh before crossing the same river once again on their return journey back to the Southern Plains.
November to December – The new return cycle
The short rains in November to December mark the start of the new migration cycle. The herds leave Maasai Mara trekking southwards to the short grass plains in Southern Serengeti. As such, the great Serengeti Wildebeest migration is a year-round continuous wildlife spectacle.
River Crossings
River crossings may be the most spectacular event of the great wildebeest migration. They occur at several different locations which include Mara river and Grumeti river. Mara river crossings happen in both northern Serengeti national park and Maasai Mara national reserve in Kenya. Mara is a fast flowing river with wide and steep banks surrounded by dense riverine forests in some sections. Due to the nature of terrain, Mara river is a preferred point for witnessing mega herd crossing spectacles. Wildebeests often jump off the steep river banks as a survival instinct. Northern Serengeti sector alone consists of over 10 Mara river crossing points including Kogatende and Lemai Wedge.
Grumeti River Crossings
Grumeti, a permanent river flowing through Serengeti national park’s remote Western Corridor is another location to witness river crossings. Grumeti is a relatively shallow moderately flowing river characterized by wide sandy channels, flood plains and muddy banks. As a result, the Grumeti river tends to attract relatively slower and quiet river crossings. The private Grumeti game reserve offers an exclusive safari for those intending to avoid crowds on a migration safari.
Predators
The migration pattern is also highly influenced by predators. Nile crocodiles become obstacles often disrupting river crossings. Big Cats which include cheetahs, lions, and leopards lurk in the plains for prey. Among other predators include hyenas, African painted dogs, and jackals. As a result, predator-prey interaction is a key highlight of the great Serengeti migration safari.
The calving season with over 8,000 calves born per day attracts predators. Cheetah sightings are common in Southern Serengeti and Ndutu Plains. Being almost treeless and flat, these areas are ideal hunting grounds favouring the high speed cheetah hunting strategy. Leopards in Serengeti national park may be spotted in Western Corridor Grumeti River, Namiri Plains, and Lobo Valley. In Mara Triangle in Maasai Mara national reserve. Lion sightings are common in the Seronera valley central Serengeti where buffaloes and zebras stay throughout the year.
The Mara and Grumeti rivers are famous for harboring a high concentration of Nile crocodiles of which Grumeti river has larger crocodiles measuring 6 feet long. Crocodiles often disrupt river crossings leading to dramatic scenes.
Scavengers including vulture species and Marabou storks play a vital role in eating the corpses of animals which maintains a healthy ecosystem.
Wildebeest Calving season
Wildebeest calving season occurs between January and March every year mainly in Southern Serengeti Plains and partly in Ndutu Plains, a transition zone between Serengeti national park and Ngorongoro Conservation Area. These areas are preferred for calving due to the nature of terrain (flat and treeless landscape), mineral salts and nutritious grass. The underlying volcanic rock formed from accumulation of volcanic ash deposits from the Ngorongoro Highlands is rich in calcium and potassium which are good for the lactating mothers and newborn calves. The rainfall pattern between November to January influenced by Lake Victoria and Indian Ocean currents help to transform the dry plains into green pastures with water-filled small salt pans scattered across the plains.
According to National Geographic, the estimated number of calves born is 8,000 per day making for over 500,000 calves born over the course of the calving season. In addition to wildebeest calves, there are other newborn wildlife including gazelle fawns, zebras foals. At the same time it is a birthing season for Big Cats where lionesses, mother cheetahs and leopards hunt to feed their cubs and teach them hunting skills.