They come like an invading swarm of locusts. Hundreds of thousands of them. They’re here for fresh grazing and they’re hungry.
In single-file they trek – long trains of animals stretching across the plain pausing only to bow their heads to take another clump of fresh grass.
As you emerge from behind the enclosing electric fence and the safety of your game lodge, you could at first be forgiven for thinking the animals have disappeared. Then – around a turn in the track – you’ll find a small group.
You pass a rotting carcass before another group scatters before you. They’re skittish animals, see.
If they don’t run as your safari van approaches, they’ll turn their heads directly towards you with a seemingly imperious stare. It’s impossible to discern an expression through the dark fur of their faces and shag of their beards.
For the wildebeest this is a time of plenty. The long grass needs to be devoured before the rains start again in the Serengeti.
It’s a time of plenty too for the Mara’s predators. Lions, leopards and cheetah all feast on the plentiful game. The plain is littered with the remains of dead animals. Dazzles of zebra also travel with the wildebeest and fall victim too. Along with eland and Thomson gazelle.
Vultures lay siege to the dead but are too fat or too full to fight over the pickings on offer.
They can’t even be bothered to scare off one of the plains’ other scavengers – the jackal – which soon has its teeth tugging at the decaying flesh.
At night we can hear the hyenas calling.
The plains’ vegetarians – the elephants, rhino and buffalo have all but disappeared. My guide Edward tells me they don’t like the rustle the long grass makes as the wildebeest move through, nor their constant porcine-like grunt that pierces the air.
One morning we head towards one of the migration’s chokepoints: the river crossings that are the deadliest part of the wildebeests’ journey.
We bump along the dirt track for hours, circling vultures indicating the location of the latest kill.
A clump of safari vans reveals a resting lion still panting from the morning’s hunt. I’m told most male lions die of heart attacks – a poor diet and too little exercise.
The King of the Jungle is said to sleep for up to 22 hours a day.
The wildebeest move slowly towards us with seemingly no destination in mind. We spot a young animal with a broken front leg. The hyenas will have it soon enough, maybe before its mother abandons it.
Still we carry on. Edward excitedly pronounces: “They’re coming from the Talek river.”
A slight in increase in speed.
As we get closer it’s clear there’s been heavy traffic here. The grassland has been bitten and trampled flat to the earth. Any animal crossing now will have to walk some distance before finding fresh grazing.
We can see a line of bushes and trees. The vegetation following the path of the river.
And finally we arrive by the water. It’s quiet. Edward explains that the wildebeest don’t use the same crossing point every year.
We drive along the riverbank a few kilometres. There’s a small herd of wildebeest eyeing the river.
“There’s not a constant stream of animals crossing. It depends on the day and the time,” says Edward.
We watch as the group edges closer to the water. Then inexplicably they turn back.
“They fear the crocodiles in the river and the lions and leopards on the other side. And they get scared. Sometimes they’ll go the whole day going back and forth, or even the next day.
“It’s like a game of dare. But once one has no fear and starts to cross, they all do.”
Edward recalls the time a few years back when the Mara river flooded after heavy rain.
“Many wildebeest drowned, others trampled on each other. You could smell death from two kilometres away.
“Crocodiles were lying on top of the carcasses. They didn’t have to hunt, it was like a party.”
Further down the river two bloated crocs lie basking in the midday sun digesting their latest meal.
A pair of hippos is submerged in the water – only occasional spurts of water revealing their presence.
There’ll be no crossing here today.