When asked to name the largest migration of mammals in the world, few would think of fruit bats. This surprising choice creates one of the most incredible aerial spectacles in the animal world.
This happens in Kasanka National park in Zambia. Way off the beaten track and one of the smaller national parks, this is a comparatively unknown phenomenon compared to the wildebeest migrations in East Africa. Between mid-October and mid-December each year up to 10 million fruit bats converge into a tiny patch of evergreen swamp forest.
While not typically at the top of the traditional safari traveller’s list; the spectacle and ecological implications of the arrival of up to 3,500 tons of flying mammals over an 8-week period, to a concentrated patch of forest is something that enthrals any nature lover.
Leaving the forest in the early evening every night, the crepuscular creatures only return at dawn. Converging and swarming to coincide with the start of the first rains, they hone in on ripening local fruit and berry species such as the masaku (wild loquat) and waterberry on which they feed.
This huge amount of flying protein naturally draws winged predators and much like the wildebeest and the lions on the plains of the Serengeti, the bats have to evade specialised hunters in the form of Crowned Eagles, fish eagles, kites, vultures and hobby falcons. The enormous martial eagle and bat hawks are also commonly seen as they hunt above the roosting site.
Witness incredible aerial dogfights as the hawks and birds of prey dive and twist after the fruit bats. The window of opportunity for the predators is brief and dramatic. As the bats take flight in a crashing rush from the branches, the hawks wait on overhead – circling menacingly.
The bats also draw ground predators and scavengers to the forest. Leopards, monitor lizards and crocodiles make off with those bats unfortunate enough to drop to the forest floor.
While sitting in a rooftop hide at the same height as the canopy of the forest, you will frequently see elephant and monkeys as well as the rare sitatunga antelope moving silently below you on the forest floor.