For many people, the aim of a trip to Tanzania or Kenya is to see the “Great Migration”. The migration is not a once-off event, it’s a continuous annual process – the explanation below shows where the main herds generally should be at any particular time, but often they are NOT – as with the early 2006 season where the big herds were all around the centre of the park in JAN / FEB, and then in the South in APRIL / MAY. They also move backwards and
forwards, and across the park, sometimes over 40 km overnight! It is also NOT one huge herd of animals, but numerous large and small herds, all with their own particular agenda.
The movement of the herds is governed by a variety of factors, each of which independently and jointly make the herds move.
• Rainfall – the time of the rains, and also the duration and intensity of the showers has an effect on the grazing and water quality.
• Water sources and quality – basically, many of the streams and rivers that cross the Serengeti have a high chloride and fluoride content. The water smells and animals do not like drinking it – a good quantity of rain will flush out a lot of salts, leaving pools of decent water… low quantity of rain will not.
• Controlled burning by National Parks and (uncontrolled) by poachers on the edge of the parks – often drives herds away, until the new grass comes back – which can often only take a week or two.
• Poaching and hunting outside the parks
• Numerous other factors – it’s not an exact science