After the rains when the first flush of grass turns the Masai Mara’s golden savannah green, the most mesmerising wildlife spectacle anywhere takes place here: The Great Wildebeest Migration. Between the months of July and October one and a half million wildebeest, accompanied by vast numbers of zebra and gazelles make the long and dangerous trek from drier lands in Tanzania, northwards to this corner of Kenya. Lines of animals stretch as far as the eye can see across the plains. They come to give birth to their young and the grasslands echo with the sounds of the new-born. It is a time of plenty. But it is a time too when the predators are drawn from all around. High above on the hot winds the carrion birds, the vultures and eagles, soar. In the long grasses lion, cheetah, leopard and hyena prowl. Most dramatic of all is the moment when the migration arrives at the Mara River. They must cross it to reach the rich grazing. As the animals throng, crocodiles cruise the waters. Then the bravest takes the plunge into the swirling currents and thousands follow.