vultures - wildlifecampus€¦ · – game ranging / field guiding course this course material is...

– Game Ranging / Field Guiding Course

This course material is the copyrighted intellectual property of WildlifeCampus. It may not be copied, distributed or reproduced in any format whatsoever without the express written permission of WildlifeCampus

1

Birds © Copyright

Module # 6 – Component # 4

Vultures

Introduction

These birds fall into the large Family Accipitridae, which also contains the kites, eagles, buzzards, hawks, harriers and the gymnogene.

Eight vulture species are found in Southern Africa. They are all typified as follows:

They are very large They have heavy hooked bills. Their necks are wholly or partially devoid of feathers, except for the bearded vulture.

They exhibit impressive wingspans, an adaption for their long time spent soaring.

All of them are scavenging species, living on carcasses located from the air. They have relatively weak feet, not suited to grasping prey. They are normally silent birds unless fighting over a carcass, when they hiss and squeal while squabbling.



2

Birds © Copyright

(Source: www.birdlife.org)



3

Birds © Copyright

White-backed Vulture - Gyps africanus

Vital Statistics

Wingspan 2.2 m [ 7.3 ft.]

Weight 5.4 Kg [ 12lbs.]

Preferred prey Carrion of any sort

Incubation period 56 – 58 days

Clutch size Single egg

IUCN Status Critically Endangered (2016)

Nesting site Tree canopies, usually Acacia Spp.

Nestling period 95 – 125 days

Habitat Open Grassland and Savanna Woodland

Home range 67 – 815 Km [41 – 510 Miles]

“Gyps” is Greek for a vulture, while “africanus” is derived from the Latin word for Africa.



4

Birds © Copyright

Description This is the most common of all the Southern African species. It is very like the

Cape vulture but smaller, with a dark instead of honey coloured eye. They are not sexually dimorphic. Their plumage is mainly buffy - white, with a white back

that can only be seen when their wings are open or in flight. When the birds get old they become very pale, and almost completely white. Their bills, legs, feet and skin are blackish, with the skin on their face and neck sparsely covered in a

whitish down.

The juvenile of the species is dark brown, with white streaks on their wing coverlets and underparts (underparts refer to the plumage that can be seen when the bird is in flight or is perched facing you). The skin on their necks is greenish,

but mostly obscured by woolly white down. Progression to adult plumage is gradual, and the change from a brown to white back is a good indication of the

bird’s age. This progression can take up to seven years, with its first moult beginning one year after hatching. These immature birds may breed at four years old, the only Southern African vulture species to do so.

White Backed Vultures with a Hooded Vulture (Critically Endangered) -

far right



5

Birds © Copyright

Reproduction During breeding, no nuptial displays appear to be performed. Copulation usually

occurs in or near the nest tree. It is a clumsy affair, with the male needing at least a minute to gain his balance, as he clutches onto the female’s ruff (neck) with his

bill. The mating only takes a few seconds, accompanied with some brief vocalisations, after which the female throws him off, or he jumps off himself. The pair then invariably preen themselves afterward.

The trees chosen for their nest site are often a species of Acacia. They nest in

loose colonies, with the nest usually being in the tree canopy. There has been some correlation between nesting sites and predator home ranges. Some birds’ nests are in the centre of lion or hyaena home ranges, presumably due to

ease of finding food. Sites may be occupied for several years in succession. The species does not appear to be territorial. There is also no evidence of co-operative

breeding. A single egg is laid between April and July (Southern Hemisphere Autumn to

Winter). The eggs are white and occasionally spotted with red. The pair share the incubation, which lasts for 56 to 58 days. The new chick is constantly cared for,

and takes its first flight between 95 and 125 days after hatching. It only becomes fully independent six months after leaving the nest.

Juvenile



6

Birds © Copyright

Sight There has been some debate as to the ability of vultures to be able to spot their

prey, as opposed to having other species doing it for them. Recent evidence now suggests that it is in fact a combination of the two. Vulture eye-sight is very

different from our own, in that the centre of their retina is overly convex. This gives the bird a centre spot of their eye-sight that is in fact highly

magnified. Therefore, their sight picture when soaring is one of a very broad view of the area in vague detail, with a highly focused enlarged area in the centre.



7

Birds © Copyright

Diet and Feeding

Feeding in vultures takes the form of a roughly repeated

pattern because of being in the same vicinity as several different species. Vultures are often led to carcasses by

Bateleurs, who have a remarkable ability to spot carrion. Their low circling descent is a signal to vultures of a potential meal. White-headed and Hooded Vultures are usually the

next arrivals, followed by the White-backed Vultures, and lastly the Lappet-faced Vultures appear.

The Whitebacked Vultures generally wait around for a while until their numbers increase, and then rush in, displacing all others. These vultures have long beaks

with a strong hooked tip and sharp cutting edges. They also have a serrated, stiff tongue, which enables them to eat very quickly. One observation showed 50

White-backed Vultures completely consume an adult impala in three minutes, with the only evidence of its presence being a patch of dusty earth where the scrimmage had taken place.



8

Birds © Copyright

Cape Vulture - Gyps coprotheres

Vital Statistics

Wingspan 225cm [90 in]

Weight 8 – 11 Kg [ 17.5 – 24 lbs.] The heaviest vulture species

Preferred prey Carrion

Incubation period 56 days


IUCN Status Endangered (2016)

Nesting site Cliff faces and ledges

Nestling period 140 days

Habitat Mountain ranges near grassland

Home range 400 – 1200 Km [ 250 – 750 miles]



9

Birds © Copyright

Description Although it has already been mentioned that this species can easily be confused

with the previous one, the Cape vulture adults are more pale, with almost white backs. This is contrasted with an ash - brown or blackish coloured trailing edges of

their wings and tail. There is also a row of black spots along the bottom edge of the upper wing coverlets, which are absent in the Whitebacked Vulture. Otherwise their bills, legs and feet are black, and their eyes are yellow. One further

very characteristic feature, are two blue eye - spots on either side of their crop, these may be concealed with downy chest feathers surrounding the base of the

neck. The sexes are alike in size and colouration. The juveniles of the species are pale brown, with a white upper chest. Their eye

- spots are also red in colour. The progression to the adult plumage is also very gradual, taking up to six years. It is also only when the birds have reached this

stage of maturity that they may breed for the first time.



10

Birds © Copyright

Reproduction The Cape Vulture differs markedly from the

Whitebacked in its choice of breeding sites, a fact which also plays the greater part in their

differing ecology and lifestyle. The Cape Vulture breeds colonially on cliffs, the only vulture in Southern Africa to do so. Because of this,

species seen in the Sabi – Sands region probably roost and breed in the nearby

Drakensberg or the Soutpansberg Mountain ranges.

Their nests are built on cliff ledges, reducing their chances of predation and disturbance.

Colonies consist of anywhere between six and three hundred pairs, although nowadays colonies of more than 100 pairs are quite rare. Nests are constructed out of collected twigs and grass, and are an

average of 70 cm [28 in.] across. The same nest sites are also used in successive years as a rule.

This species has the same rough breeding season as the Whitebacked,

but with a peak of egg laying in May. The Cape Vulture also shows a high degree

of synchronicity in egg laying in the same colony. The normal clutch size is a

single egg, which is chalky white. Incubation is shared by the pair, and usually lasts for approximately 56 days.

Once the nestling has hatched, both parents take turns in feeding it, by mouth

to mouth regurgitation. The nestling period is about 140 days, although the adults will continue to feed it even when

the young are fully grown.



11

Birds © Copyright

Flight Vultures, being the large birds that they are, prefer soaring to powered flight.

This is of course an adaptation to lifestyle, as the birds spend much of their time, soaring high above the ground in search of food or other species that pin -

point food for them. These other predators or scavengers include Bateleurs, Pied Crows and White Necked Ravens, jackals or hyaenas. Most vulture species depend on warm thermal currents for an initial lift into the air, and all

subsequent gliding. These vultures don't have exceptional eyesight attributed to most birds of prey. Recent studies suggest that they don't spot carcasses from

high altitude, but take their cues from other birds flying closer to the ground.

The Cape vultures gain an added advantage from the fact that they nest on cliff faces. Up draughts against the cliffs give them an initial lift, before a thermal can be found. This also means that they can become airborne earlier in the day,

not having to wait for warm thermal air currents to develop.

Thermal air currents develop because of convective heating of the ground (incoming solar radiation heating the earth’s surface). However, as these birds may not necessarily nest in the same area as they forage, the advantage of early

mobility may be overridden by the distances they must travel to get to their food.



12

Birds © Copyright

Conservation Status The fact that the Cape Vulture lives

outside of its foraging areas brings up another very salient point. This is the

fact that numbers of this species have been steadily declining, to the point that special conservation

measures have had to be brought into play to arrest this decline. The

vulture being a scavenger, does not restrict itself only to game carrion, but consumes any form of carrion

available. Thus, some colonies sustain themselves almost exclusively on the

carcasses of domesticated animals such as sheep and cattle.

However, from a farming point of view, a dead animal is a potential

danger of disease for the rest of his herd. Also, dead animals attract other scavengers such as feral dogs and jackals. These animals pose a risk of hunting other stock animals. Farmers deal with this problem in a few ways. The carcass of

an animal may either be buried or burnt, thus depriving all the scavengers of a meal. But more seriously, some farmers have resorted to poisoning the

carcasses to eliminate the mammal scavengers from their areas. However, even though the vultures pose no specific danger to the farming operation, many

are killed while feeding off a poison - treated carcass. Other hazards that the Cape Vulture faces are the fact that they are occasionally

killed by powerlines, either being electrocuted or colliding with unseen lines. Vultures also rely on a supply of bone to take back to nestlings as an essential

source of calcium. However, as carcasses become rarer, the birds inadvertently bring back bits of china, glass, metal and plastics, all useless as a calcium supply.

This deficiency leads to metabolic bone disease. Fortunately, this situation has

been remedied to a degree by the establishment of "Vulture restaurants", where a carcass with crushed bones is put out near protected breeding colonies to encourage further breeding.



13

Birds © Copyright

Lappet-faced Vulture - Torgos tracheliotus

Vital Statistics

Wingspan 2.6 m [ 8.5 ft.]

Weight 7 – 10 kg [15 – 22 lbs.]

Preferred prey Carrion

Incubation period 56 days


IUCN Status Endangered (2016)

Nesting site Tallest available tree

Nestling period 125 days

Habitat Open grassland and Savanna woodland

Home range 700 Km [ 437 miles]



14

Birds © Copyright

Description

Although none of the vulture species can ever be described as attractive to look at, the lappetfaced is certainly the most impressive, and the most distinctive of the

common Southern African species. It is the largest vulture, although the Cape Vulture weighs more. This species has a characteristic red and wrinkled head. Its lappets or lobe - like folds of skin on its head account for its name, and they

are present from hatching. The adults have predominantly black plumage, with thick white down on their upper chest and on their legs, which gives the bird the

appearance of wearing trousers. They also have a massive pale yellow bill, and black eyes. Their feet, legs and cere (basal part of its bill) are blue.

The juveniles of the species differ in having blackish - brown trousers and greyish down on their chests. Ageing of the young can be calculated by looking at the

degree of whitening of their tibial (legging) down. In accordance with the other vultures already examined, the birds take five to six years to mature.



15

Birds © Copyright

Reproduction Lappet-faced vultures normally build their nests in the tallest trees in the area.

Their nests are also very large, averaging over 1 ½ m [± 5 ft.] in diameter. These birds breed once every two years, unless a clutch or brood is lost.

One egg is laid between May and June. Incubation of the egg takes around 56 days, and again all duties concerning the egg and nestling are shared. The nestlings

take their first flight at approximately 125 days, and gain full independence five months later.



16

Birds © Copyright

Diet and Feeding When discussing the general feeding of vultures, it was mentioned that the

Lappetfaced vultures were usually the last to arrive at a carcass. However, when they do arrive, they immediately dominate all other species at the feeding site.

That depends on whether they get involved in disputes with others of the same species, which they frequently do. Arriving late at a carcass may mean little is left to eat for most vulture species. However, the Lappetfaced is the only species that

can deal with the tougher skin and bones. It can also open a carcass of a thick-skinned buffalo, elephant, hippopotamus or rhinoceros, where the others

cannot. One further aspect that differentiates the lappetfaced in feeding is that it is

considered a clean "outside" feeder. The Whitebacked and Cape Vultures are "inside feeders", which means they happily gorge themselves into the carcass,

with their heads and necks inside the animal. The Lappetfaced, however, prefers to eat from the outside and does not soil its plumage. This though makes them slower feeders. This is not to say that the other faster feeding vulture species

are continually unkempt. Quite the contrary. When the Whitebacked and Cape Vultures feed messily and coat themselves in caked blood and dust, they

will soon bathe themselves and preen their plumage.



17

Birds © Copyright

Conservation Status Of these three species, the Lappetfaced is the most threatened in terms of

diminishing numbers. The population may now be regarded as endangered.

(Photographer: Martin Brasg)



18

Birds © Copyright

Vulture Restaurants

Vulture restaurant is a safe

feeding site where animal carcasses, both domestic

and wild animals of any shape or size, are provided as an artificial

food source for vultures on a regular basis. This

practice not only serves to assist in the continued survival of our vultures, but

also increases the awareness of the vultures’

plight by involving communities throughout a large part of the vultures’

home range.

Although vulture restaurants can improve the wellbeing of vulture colonies throughout South Africa, the recent crash in India’s vulture population has raised major safety concerns on the practice of allowing vultures access to

carcasses with chemical residues and/or lead. Carcasses at restaurants or left in the veld (by farmers) can be from animals treated with a veterinary drug, for

an illness, and has thus raised the question:

If diclofenac, a rather innocuous veterinary non-steroidal anti-inflammatory agent could lead to a 98% vulture declines, what damage could other toxic compound such as the organophosphors cause? (Swan et al., 2006)

Even the influence of a simple lead bullet is not known. Due to the costs of

euthanasia, many farmers and veterinarians routinely put down animals with a lead bullet to the head. In the case of hunted wildlife, this could include numerous shots, of which one is often to the heart. With lead toxicity known to be a problem

for other raptor and vulture species exposed to lead shot in carrion, the effects of lead exposure also require clarification in our birds (Garcia-Fernandez et al., 1920;

Adaudi et al., 1990; Mateo et al., 1997; Platt et al., 1999; Clark and Scheuhammer, 2003).

Because vultures congregate at carcasses and vulture restaurants, significant proportions of the population can be exposed to whatever residues there may

be in the carcasses. As this is an emerging hi-tech man-created situation, it is our responsibility to be pro-active in minimising this potentially devastating threat to the free-ranging vulture populations in southern Africa.



19

Birds © Copyright

What not to feed:

Body parts or flesh through which a bullet may have passed or lodged. Cut off the animal head or part where the bullet went through as well as the surrounding flesh where the bullet could have fragmented.

Meat/carcasses which have not been free of all medication for at least one week before the animal died.

Carcasses previously treated with flunixin (Finadyne ®, Cronyxin ® and Pyroflam ®) or ketoprofen (Ketofen ®) or phenylbutazone (Tomanol ®, Phenylarthrite ®, Equipalazone ® or Fenylbutazone ®).

Carcasses that were euthanased with pentobarbitone (Euthanase ® and Euthapent ®)

Game carcass that died following drug immobilizing e.g. M99 ®, Zoletil ®, Dormicum

Carcasses that were recently treated for ticks or for tick-bite fever (Redwater) If there is any uncertainty about the quality of a carcass, it is recommended that

the liver and kidneys be removed and destroyed prior to placing out the carcass, as these organs often contain the highest concentrations of deleterious drugs.

While this will reduce the likelihood of toxicity, euthanasia agents and the capture drugs might still be toxic in the meat and in this case the carcass is best not offered to the birds.

Extract taken from the African Indaba Newsletter with the kind permission of

Kerri Wolter.



21

Birds © Copyright

(Image source: www.vulpro.com. To support this important organisation, please visit their

website for more information on what you can do to help)

http://www.vulpro.com/



22

Birds © Copyright

(Image source: www.vulpro.com. To support this important organisation, please visit their

website for more information on what you can do to help)
http://www.vulpro.com/

vultures - wildlifecampus€¦ · – game ranging / field guiding course this course material is...

Documents