One column turns to the north while another column turns to the west, later turning eastwards to join the northern column. Then, together the whole herd finally returns to the central plains, completing the circle. About 1000 kms are thus covered.
As the herds move to new grazing ground, they are followed by predators such as lions, hyenas, jackals and hunting wild-dogs waiting for weak prey while vultures soar overhead waiting for their share of the kill. Best time for visiting is December - May when the animals are gathered on the short grass plains south of serengeti around Ndutu and Naabi Gate, dispersed and moving back sand forth in search of water and fresh grass until the end of the long rains.
Calving takes place in February/ March, when 90% of female wildebeest give birth, flooding the plains with thousands of young ones. In may, when pains begin to dry up, the wildebeest, together with other animals begin the long track westwards or northwards once again. The migration involves between 500,000 - 1,000,000 animals out of the 4,000,000 found in Serengeti.