Since the migration lasts all year, you can travel at any time and see part of this astonishing spectacle. That said, with the migration constantly moving, seeing the highest possible concentration of animals means travelling to where the herds are at any given time. Wilderness Usawa Serengeti is one of the most mobile luxury operations in the Serengeti; with access to nine key migratory sites, proximity to the herds is guaranteed. The numbers really boom in calving season, when the wildebeest give birth to their young, and this usually occurs between January and March. The best time to see dramatic river crossings is between July and October.