Raptor Series: Eagles

Most of the birds we will be looking at in this series are members of the family of birds known as acciptridae (from the Latin, meaning ‘hawk’ – or ‘someone who behaves like a hawk’!).  That includes the birds in this article: eagles. This is often shortened in English to ‘accipiter’, and you may come across this term as well.   There are raptors from other non-accipiter families that we will also look at, namely the Secretary Bird (from the family sagittariidae, from the Latin, meaning an archer i.e. one who uses a bow and arrow) and some falcons (from the family falconidae, from the Latin falco, meaning, well, falcon).  

These scientific names are based on the structure of the birds, which is to say, basically on their appearance, and does not indicate the taxonomy or relationship between types of birds according to the way these creatures evolved (that is “what species developed out of which species” which are now being revealed by modern DNA analyses and showing some surprising connections).   

In this article, we shall look briefly at five examples of eagles, at least four of which you are somewhat likely to have seen already.  These are the Fish Eagle (hungwe, in Shona), the Bateleur (chapungu, in Shona), the Black Eagle, also known as Verreaux’s Eagle (rovambira, in Shona), the Martial Eagle, and the Long-crested Eagle (kondokondo or pfinye in Shona).  I should say that I am relying on Robert’s Field Guide for these Shona names, which is a bit problematic: it seems likely that the same bird might have different local names in different localities within Zimbabwe, and also that the same name may, in different places, be applied to different birds. 

I was told once, when I asked for the Shona name of the Crowned Eagle, that it was called dorambudzi but it might be that this name could be attached to any eagle large enough to take a goat.  I apologise for not giving the local names in any other Zimbabwean language.  

AFRICAN FISH EAGLE

Haliaeetus vocifer [haliaetus, Greek: a fishing eagle; vocifer, Latin: vociferous, noisy]

This middle-sized eagle is a very common sight seated on a dead tree alongside dams or lakes in Zimbabwe, from which they can get a good view of the water and the movement of fish: I have seen one at Mukuvuzi Woodlands in the outskirts of Harare.  The call, which you can hear here (https://soundbible.com/552-African-Fish-Eagle.html) is very distinctive and carries a good distance, especially over water.  They are resident, meaning that they do not migrate, and sedentary, meaning that they occupy a specific territory. 

Young fish eagles – the parents can sometimes raise as many as three young at a time if food is plentiful and if the stronger chicks do not kill their weaker siblings – have to travel long distances to establish their own territories.  Adult pairs stay together (they are monogamous) and may use the same next over many years.  Adult males aggressively defend their territories, sometimes engaging in aerial battles, interlocking feet with their opponent in mid-air and ‘cartwheeling’ downwards to separate just before hitting the ground. 

As the name implies, they feed on fish, snatched expertly from just beneath the water or, with bigger fish dragged through the water to shore; but they also eat plenty of other things – water birds, mammals such as rock hyraxes and monkeys – when there is not enough water.  

BATELEUR

Terathopius ecaudatus [terathopius, Greek: a expert juggler; ecaudatus, Latin: lacking a tail] 

This is one of the smaller of our eagles, only 63cm in length, but it is particularly striking in appearance and easily recognisable whether perched or in flight.  In the picture above right, the thick black trailing edges to the wings indicates a male; the female has a much thinner black edge. 

It’s not true, as the Latin name suggests, that it has no tail; but its tail is very short and in flight the feet hang out at the back.  They are common in certain areas with open savanna or mopane woodland, but not so much in mountains or forests. 

The name ‘bateleur’ is French for a juggler, and this bird is known for some dramatic kinds of ‘aerobatics’ with spectacular swoops and dives in its courtship behaviour, sometimes performing ‘snap-rolls’ in which, flying at speed, it suddenly flips over making a sound with its wings (making it the only eagle that deliberately makes a sound with its wings), or ‘limp-wing’ displays, flying with wings half extended, feet extended and head erect. 

Much of their flight depends on upward drafts, and so it is essentially grounded on dull or rainy days; indeed, it can spend quite a lot of time on the ground, or even standing in water with its wings extended as if sun-bathing.  It eats a wide variety of different creatures, much of it scavenged (i.e. feeding from already dead animals).  

VERREAUX’S EAGLE or BLACK EAGLE

Aquila verreauxii: [aquila, Latin: eagle; verreauxii, named after brothers Jules (d.1873) and Edouard Verreaux (d.1868), French collectors who worked in the Cape, South Africa, and after whom a number of species have been named]

This extremely impressive bird may be the biggest of our eagles, measuring from 80 to 96cm in length (that is, not so far from a metre!) with a wing-span of 2 to 2.8m (Roberts, Birds of Southern Africa VIIth Ed.).  It is entirely black, apart from yellow skin around the eyes, nostrils (its ‘cere’) and toes, and a white patch on its back which, when seen perched from behind, looks like a V and, when seen in flight from above, looks like an X-shaped cross: in Afrikaans, it is known as the Witkruisarend or ‘White-cross Eagle’. 

This enormous bird inhabits mountainous regions with rocky cliffs for nesting and hunting, and is a ‘must-see’ in the Matobo National Park.  They mostly feed on Rock Hyraxes (mbira) but also baboons and monkeys and other birds.  They sometimes use surprise attacks on their prey but they also will deliberately induce panic among their prey, with one eagle swooping overhead to frighten their victims while its mate follows closely behind to snatch the fleeing animals or cause them to fall to their deaths. 

It has been reported that one pair of these eagles in Namibia chased a Kudu calf over a cliff to its death.   Mating pairs stay together for years, continuing to use the same nest: their courtship behaviour also includes spectacular tricks, such as carrying a stick up high, dropping it and rolling over to swoop down and catch it again before it hits the ground.  They also can be involved in the same ‘cartwheeling’ struggle with intruders, with feet interlocked until just above the ground.  

MARTIAL EAGLE

Polemaetus bellicosus: [polemaetus, Greek: war-like eagle; bellicosus, Latin: war-like]

This is another large eagle, up to 83cm long and a wing span of up to 2.4m (according to Roberts).  It is not the biggest eagle: both Verreaux’s and the Crowned are bigger than this one.  But the Martial is without doubt the most awesome.  They are said to be widely distributed across southern Africa, but they are not many of them and so they are rather rare and are classified as ‘vulnerable’.  I think I saw one, and possibly a nesting pair, in Hwange but I may have been mistaken; if I did, I did not know how lucky I was. 

Soaring very high up, this bird can spot its prey from 6km away: rock hyraxes and monitor lizards but also mammals as big as impala (as you can see from the photo above), jackals, cobras and other snakes, and even tortoises.  It does not seem to be true of this Martial Eagle, but there are stories of another very large eagle, the African Crowned Eagle (not featured here), sometimes attacking humans, which is to say, children; part of a child’s skull has been found in a nest of the Crowned Eagle. 

Amazingly, the famous fossilized skull of a child of an early human species, Australopithicus africanus, discovered in 1924 in South Africa and now known as the ‘Taung Child’ and estimated to be about 2.3 million years old, is said to show the marks typical of a kill by one of these Crowned Eagles (or whatever forebears of our Crowned Eagle that flourished at that time).  

LONG-CRESTED EAGLE

Lophaetus occipitalis: lophaetus: Greek, a crested eagle; occipitalis: Latin, at the back of its head

This is one of the smallest and, at least in my experience, most commonly seen and easily identified of our eagles.  It is often to be seen perched conspicuously on a telephone or powerline pole at the side of the road; individuals often have a favourite place to perch and regularly return there.  I have even seen one perched on quite a low durawall between two properties in Mount Pleasant, the Harare low density suburb: quite a surprising perch for an eagle! 

In flight, its underwing pattern is also pleasingly easy to recognise: above you and against the sky it seems all black but with two white ‘windows’ i.e. white patches, one at the end of each wing; as you can see from the picture above right.  They are sedentary, meaning they occupy and defend a definite territory and can normally be found there. 

They eat rats and mice, more occasionally other small birds, and a great variety of other creatures such as frogs, snakes, lizards and crabs but also locusts and millipedes and fruit such as figs and mulberries.  The number of these birds has increased in Zimbabwe.