“No other eagle can match the magnificence and fluent flight of these hunters of the hills.” ~ Peter Steyn, renowned South African ornithologist.
The African Fish Eagle is a well-known sight and song on our river and across Zambia, so much so that it’s on the national flag and is endearingly called, The Call of Zambia. But there are many other fascinating eagles to be on the lookout for in Zambia. We’ll be introducing you to a few more. Recently we spotted one particular eagle – the Verreaux’s eagle – on a trip to Chinzombo in South Luangwa, but this bird of prey also frequents our river closer to home.
From the sheer rock walls of the Batoka Gorge below the Victoria Falls, one side in Zambia and the other in Zimbabwe, to the inaccessible ledges and crags of the natural wonder that is Table Mountain in Cape Town, South Africa, the rock hyrax keeps an eye out for the Verreaux’s eagle. In fact, the rock hyrax or ‘dassie’ accounts for up to 90% of this specialist hunter’s diet.
Many predators have honed their skills and hunting techniques over hundreds, maybe thousands, of years, causing their bodies to evolve until they are truly natural wonders. The cheetah has ‘running shoe’ claws and a ‘rudder’ tail that contribute to its speed and ability to jink and swerve at full speed. Many species of vultures have the unusual, among birds, ability to detect their dead ‘prey’ by smell and their featherless heads and necks are designed for poking deep within rotting carcasses. While many eagles have the ability to ‘lock’ their wings in position to enable them to glide and soar for hours, the Verreaux’s eagle is a master of aerial manoeuvrability.
The wings of Verreaux’s eagles allow them to navigate the air currents that are channeled and directed through the Batoka Gorge, downstream from us on the Zambezi, and the tumultuous gales that are common around Table Mountain.
According to Rob Davies, a raptor biologist, they are able to “fly in a gale of 157kph, draw their wings in slightly and make progress into the eye of the wind, while other birds are being flung across the sky.” While the hyraxes duck and dive and generally make themselves unavailable for lunch, these eagles use not only their mastery of the sudden appearance, supported by nothing but air, to ensure that their chicks are fed, and their big feet.
While the osprey has structures on its toes called spicules and is the only hawk that has a “reversible” toe, features that help it to grasp its slippery fish prey, the Verreaux’s eagle has feet that are roughly 20% bigger than would be expected for a bird of its size and this makes grabbing the not-so-slim hyraxes considerably easier. Its feet must also help when hyraxes are scarce and opportunistic hunting of prey as varied as tortoises and impala is called for.
The rock hyrax lives at elevations of up to 4200 meters and they post a sentry that warns of danger and allows them to scurry into any close by crevice, but, smarter than the average hyrax, a pair of Verreaux,s eagles will often hunt as a team, with one acting as a distraction and the other swooping in for the kill.
Verreaux’s eagles live where they hunt, on the rocky ledges on mountain cliffs and on the steep sides of gorges cut into the earth by mighty rivers, ledges that are inaccessible to almost all predators with an eye for Verreaux’s eagle chicks. These apex predators are monogamous and have been known to live to 40 years of age in the wild. As a rule, two eggs are laid in a nest that hugs the mountain-side, but unfortunately the Verreaux’s eagle practices ‘obligate siblicide’ where, if two chicks hatch, the younger of the two almost always succumbs to starvation and bullying by the elder chick.
The adult eagles do, however, have a trick up their sleeves when it comes to preparing their youngster for the big bad world. Tough love from Verreaux’s eagles comes in the form of a period of aggression towards the juvenile. During this time the young eagle is still fed and supported by the parent eagles while they regularly ‘attack’ it. This is done not only to encourage the fledgling to leave the nest but also so that it can learn the skills required for aerial combat. While the young of lions and African wild dogs acquire the necessary skills through rough and tumble games with their siblings, the ‘only child’ juvenile Verreaux’s eagle must practice on its parents.
Birds of prey have always fascinated us as members of an elite group of birdlife, and the Verreaux’s eagle is certainly one worth trying to spy on and learn more about.