Every July, roughly a million and a half wildebeest push north out of the Serengeti and into the Maasai Mara. The crossings at the Mara and Talek rivers are the moments people picture — but they are also the least predictable part of the whole spectacle.

We plan departures between mid-July and mid-October, with the highest crossing probability in the first three weeks of August. Rather than parking at one crossing point for hours, our guides work the radio network and move between Lookout Hill, Paradise Plain and the Talek confluence.

If your priority is the crossing itself, budget at least three nights inside the reserve. One-night trips can be magnificent, but they turn a natural event into a lottery ticket.

Shoulder season has its own argument. In late October the crowds thin, the light is softer, and predator sightings are often better because the resident prides are still fat and confident on the retreating herds.