Ever so batty about Zambia
A ringside seat for the biggest winged migration in the world
WITH bellies full of mango, they fly in exhausted. All night they have been gorging on the fruits of the forest. At about 5am, as the sun starts to rise, they return home to digest their fruity bounty.
Hundreds soon become thousands and tens of thousands become hundreds of thousands until the lightening sky above me fills with millions of furry, fruitstained, winged creatures.
They are fruit bats (or flying foxes), and with straw-coloured, puppy-sized bodies and wings that span almost 1m, these are giant fruit bats. All are looking for a roosting space and competition is fierce in this small patch of remote swamp forest in Zambia’s Kasanka National Park.
From my treetop hide, about 20m above the ground, I am almost at the same height as the bats. Against a backdrop of a crimson sky, the sight of millions of these creatures silhouetted against the early morning sun is startling. Graceful as trapeze artists, the bats dive in and out of the forest’s towering trees, chattering and squealing loudly. Landing on the trunks of red mahogany and milkwood trees, they crawl up into the branches, nudging, shoving and bumping each other until they find a free space from which to hang upside down.
The trees swarm with bats. Wriggling and jiggling, they pack tightly, like grapes, into clusters and begin to settle down. After a night of flying and foraging they are exhausted. Brown leathery wings are pulled in over honeycoloured tummies. Bright orange eyes, housed in faces as sweet as a puppy dog’s, start to close.
As they drift into sleep, birdsong, gentle as a lullaby, gradually replaces the high-pitched din of the bats. The forest, now an enormous bat dormitory, falls quiet.
With an estimated 10 million (possibly as many as 15 million, according to some figures) bats snoozing here from late October to the end of December, this is the largest bat roost on earth. From the neighbouring Democratic Republic of Congo, millions of fruit bats migrate, regular as clockwork, every year.
Gastronomic tourists with huge appetites, they come in search of seasonal waterberries, mango, wild loquat and red milkwood berries. While they are in Kasanka, the bats eat their way through the forest, each feasting on about 2kg of fruit every night. By the time the bats leave in late December, the trees are stripped bare; more than one billion pieces of fruit will have been devoured.
Such is the draw of this ambrosia that the number of bats migrating here is more than 10 times the number of mammals involved in Africa’s most famous wildlife spectacle, the annual migration of 1.8 million wildebeest between the Masai Mara in Kenya and the Serengeti in Tanzania.
The fruit bats’ migration from the Congo Basin to Kasanka is actually the largest mammal migration on earth. And it happens in a pocket of forest no bigger than two or three football pitches, in one of Zambia’s smallest and least-visited national parks.
Kasanka covers a stretch of just 390sq km but what it lacks in size (by African game reserve standards) it makes up for in biodiversity. As well as the swamp forest so loved by fruit bats, Kasanka fea- tures an incredible array of habitats. There are grasslands and plains, dry woodlands and thickets, riverine areas and lagoons.
In turn, this diversity of habitat supports an array of wildlife. With more than 410 bird species counted at Kasanka, twitchers find the territory outstanding; Pel’s fishing owls, wattled crane, Ross’s lourie and various species of eagle all share habitats here.
It’s not home to all of the big five, but the park has growing numbers of monkeys, baboons, jackals, hyenas, civets, genets, hippos and elephants. There are also numerous antelope species, including the world’s densest and most visible population of sitatunga, one of Africa’s least-seen deer.
Recently, lions and leopards have been seen, and with the odd predatory big cat around, Kasanka takes no chances with the safety of visitors. Walking to the bat hides in the swamp forest, I am accompanied by both guide and armed escort.
Kasanka is a safe place for bats in the main, but tucked under trees on the banks of the Musola and Kasanka rivers that converge here, crocodiles lie in wait. For, now and again, branches made weak by the weight of dreaming masses of bats will break away.
Tumbling down into the jaws of the crocodiles, sleepy fruit-filled bats make a welcome swamp snack for stomachs.
While heavy with dozing bats, none of the branches here seems likely to snap. The forest is still and bathed in sunlight. I climb down from the hide; it’s time to leave the bats to their slumbers.
They will wake just before twilight. Ravenous, they will chatter and squeal, fidget and preen. Then, as the sun bids farewell to the day, they’ll take off in search of those berries and fruits. And by the light of the moon, in my treetop hide, I’ll again be watching, marvelling as the amazing spectacle unfolds.
Fruit bats in Kasanka vie for a space to roost