Mighty Migrations: Summer Edition
The Okavango is a place that never stands still. Rainfall levels both at home and abroad, migratory patterns of large herbivores, and the activity of termites creates a system that’s constantly in flux. It is thanks to this that the Delta is home to such an extraordinary abundance and diversity of animals, some of whom travel for thousands of miles to be here in the right season. The transition from the dry to rainy season causes an unbelievable transformation. Within a matter of days, the Delta turns from dust to an arena of life, dominated by dazzling hues of green. Grasses bloom from thick sand, trees find their leaves again and all around life blossoms. In this blog, we pay homage to two lesser-known winged-species who endure epic migrations to capitalise on this time of plenty, whose arrival in Botswana means only one thing. Pula!
A boom of new life accompanies the arrival of the rainy season. Photo credit: Hannah Gormley
The first of these to arrive is the conspicuous Woodland’s Kingfisher. With their bright blue colours, black shoulder stripe and white belly, they’re impossible to miss. These migratory birds spend their winters in the warmer pastures and better grazing ground up north. Contrary to their names, the Woodland Kingfisher doesn’t actually fish. Instead, they hunt for prey from forest branches. To see their electric-blue bodies bolt past you as they catch insects mid-flight or an unsuspecting small vertebrate on the ground is a sight to behold. Then begins the gruesome, yet fascinating, process of watching them beat their captive creature to death. Just like Carmine bee-eaters, the arrival of their striking colours and unmistakable call heralds the start of the summer rains and possibly the most beautiful season in the Okavango Delta.
The Woodland's Kingfisher, our conspicuous summer visitor.
A very different migration is that of the Brown-veined Whites who arrive in the midsummer months and emigrate out a few days later. Each year, in a spot in the South Western corner of the Kalahari, millions of caterpillars gorge themselves on the abundant Shepherd trees that grow there. As their numbers multiply and the plants dwindles, the population explosion triggers an instinctive mass movement in a north-easterly direction. On average, only one in a hundred will survive through to adulthood, and that’s only the start of their adventure. At the start of the rains, a fragile force of millions of Brown-veined Whites takes to the air to reach their unknown destination on a perilous journey. Hordes of insect-eating birds and dragonflies accompany them and they must drink every 20-minutes or face death from dehydration. Those few who do survive scatter their eggs along their path until they reach the shores of Mozambique, which marks a tragic end to their epic journey.
A brown-veined white in flight. Photo credit: Hannah Gormley
While we enjoy an entire season of the Woodland Kingfisher and just a few days of the Brown-veined Whites, we are equally grateful for the arrival of both. Every animal, plant, fungi or bacteria plays an invaluable role in this ever-changing ecosystem, and the disappearance of one spells disaster for the countless of others that rely on them. But it’s more than that. It’s hard to describe the feeling of being surrounded by thousands of butterflies or listening to the shill-cry of a Woodland’s Kingfisher. Climate change threatens these extraordinary behaviours, as well as so much else on our delicate planet. Let these small but mighty animals be a reminder that it’s not too late. We can prevent the worst impacts of climate change if we work together. Coronavirus might be an inconvenience, but it has taught us some important environmental lessons to help us, like: do you really need to fly to New York for that business trip? Or take the car to the office every day? The actions you take really will make the world of a difference.
Written by Hannah Gormley and Amy Beattie