Jonathan Scott: The greatest spectacle of the natural world

I watched as the wildebeest, zebra and gazelles moved in the wake of the rains. At first it seemed innocuous enough, nothing more than a pleasing breeze each morning, but the muddy waterholes were already retreating. Then the dry north-easterly winds picked up to continue unabated, gusting night and day. The wildebeest turned their backs on the stinging wind and, like a river in flood, began to stream off the plains, drawing to them tributaries of animals from every corner of the land.

Lions and leopards looked down on the herds from among rock and tree; for as long as the animals continued to pour over the horizon the predators would have no difficulty finding food.

Early one morning, I met the great armies of wildebeest marching through chest-high grasslands. I pulled off the road and watched in awe as wave after wave of animals crested the rise, cropping the grass as they surged forward. Within minutes they were lost to the naked eye. The long march to their dry-season pastures was in full spate.

There is nowhere else on earth where you can see such an incredible array of animal life - more than two million ungulates, together with the predators that feed on them. Here the game still survives, unchanged for thousands of years despite the periodic devastations wrought by disease and drought and the ever-present threat of the poachers. Perhaps the Serengeti and Masai Mara will survive, but only if we want them to.

The writer, film-maker and photographer Jonathan Scott has studied the migration for 20 years, spending much of his time living in the Masai Mara. He is a past winner of the BBC Wildlife Photographer of the Year award.