Nesting patterns of raptors; White backed vulture (<i>Gyps africanus</i>) and African fish eagle (<i>Haliaeetus vocifer</i>), in Lochinvar National Park on the kafue flats, Zambia

doi:10.4236/oje.2013.35037

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Vol.3, No.5, 325-330 (2013) Open Journal of Ecology

http://dx.doi.org/10.4236/oje.2013.35037

Nesting patterns of raptors; White backed vulture

(Gyps africanus) and African fish eagle (Haliaeetus

vocifer), in Lochinvar National Park on the kafue flat s,

Zambia

Chansa Chomba1*, Eneya M’Simuko2

1Disaster Management Training Centre, Mulungushi University, Kabwe, Zambia;

*Corresponding Auth o r : [email protected]m, [email protected]

2School of Natural Resources, Copperbelt University, Kitwe, Zambia

Received 29 May 2013; revised 29 June 2013; accepted 15 July 2013

bution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly

cited.

ABSTRACT

This study assessed the nesting patterns of

raptors, Gyps africanus and Haliaeetus vocifer

in Lochinvar National Park. The main objective

of the study was to determine whether tree spe-

cies, height, girth size, and habitat influenced

raptor’s nest placement within Lochinvar Na-

tional Park. Two species were selected as indi-

cator species for the raptors. Habitat types and

tree species were identified and measurements

of tree species with nests measured. It was

found that the minimum height of nest place-

ment was 10 meters above ground and Acacia

woodland was found to be the most preferred

habitat for nest placement. Raptors avoided hu-

man disturbance by placing their nests at least

100 meters away from human disturbance and

from the National park boundary inwards or

abandoning if human encroachment comes

close to the nest. More research is required to

assess nesting materials u sed, and to d eterm ine

whether raptors can swap nets or return to the

abandoned nests when human disturbance

ceases.

Keywords: Raptors; Nest Placement; Tree Height;

Lochinvar; Kafue Flats; Habitat

1. INTRODUCTION

Raptors are birds of prey which are on top of the food

chain and as such play an important role in overall fun c-

tioning of ecosystems. The word raptor is derived from a

Latin word raptare meaning to seize and all raptors are

biologically characterized by hooked bills and keen eye-

sight as well as powerful feet with sharp talons. This

group of birds is facing global challenges due to habitat

loss and reduction in prey species usually in competition

with man. In this study, which was carried out in

Lochinvar National Park, on the Kafue Flats, Zambia,

two species of raptors; white backed vulture (Gyps afri-

canus) (Figure 1) and African fish eagle (Haliaeetus

vocifer) (Figure 2), were chosen as representatives of the

group, as they are both susceptible to habitat conversion

and loss of prey.

The white backed vulture for instance, faces similar

threats to other African vultures, of being susceptible to;

habitat conversion due to expanding agro-pastoral sys-

tems, loss of wild ungulates leading to a reduced avail-

ability of carrion, hunting for trade, persecution and poi-

soning. In East Africa, the primary issue is poison ing [1]

particularly from the highly toxic pesticide carbofuran,

which o ccur s primar il y ou tsi de pro te cted areas . Th e large

range size requirements of this and G. rueppellii species

puts them at significant risk as it means they inevitably

spend considerable time outside protected areas [2]. Re-

cent evidence from wing-tagging and telemetry studies

suggests that annual mortality, primarily from incidental

poisoning, can be as high as 25% for G. africanus

(Kendall and Virani in press). In addition, the ungulate

wildlife populations on which this species relies have

declined precipitously throughout East Africa, even in

protected areas [1]. In 2007, diclofenac, a non-steroidal

anti-inflammatory drug often used for livestock, and

which is fatal to Gyps spp. when ingested at livestock

carcasses, was found to be on sale at a veterinary practice

in Tanzania. It was also reported that in Tanzania, a Bra-

C. Chomba, E. M’Simuko / Open Journal of Ecology 3 (2013) 325-330

326

Figure 1. White backed vulture on a perch. Large tall trees are

important for perching but branches must be large enough to

support the weight.

Figure 2. Type of nest used by fish eagle. The nest is usually

large measuring about 2 meters across and made of principally

twigs.

zilian manufacturer had been aggressively marketing the

drug for veterinary purposes and exporting it to 15 Afri-

can countries [2]. In southern Africa, vultures are caught

and consumed for perceived medicinal and psychological

benefits and the decline and possible extirpation in Nige-

ria has been attributed to the trade in vulture parts for

traditional juju practices. As a result of this and envi-

ronmental pressures, it is predicted th at the population of

G. africanus in Zululand could be become locally extinct

in 26 years, unless harvest rates have been underesti-

mated, in which case local extinction could be 10 - 11

years away. There is evidence that it is also captured for

international trade; fo r example in 2005, at least 1 3 indi-

viduals of this species being kept illegally in Italy were

reportedly confiscated. Electrocution on power lines is

also a problem in parts of its range, and it is vulnerable to

nest harvesting or disturbance by humans [1]; perhaps

more so than G. rueppellii, as it breeds in trees rather

than on inaccessible cliffs.

The African Fish Eagles unlike the true fish eagles

(Ichthyoph aga) [3] are mainly fresh water birds and ind i-

genous to sub-Saharan Africa, ranging over most of con-

tinental Africa south of the Sahara Desert and are is still

quite common near freshwater lakes, reservoirs, and ri-

vers. It requires open water with sufficient prey and a

good perch. This is evident by the number of habitat

types that this species may be found in, including

grassland, swamps, marsh e s , tropical rainforest, fynbos

and even desert bordering coastlines, but absent from

arid areas with little surface water. Its choice of habitat,

along water bodies often brings it in direct competition

with humans, particularly fishing communities.

Fish eagles have a remarkable breeding behaviour.

They pair up and mate for life. Pairs often maintain two

or more nests, which they will frequently re-u se. Because

nests are re-used and built upon over the years, they can

grow to be quite large, some reaching 2 m across. The

nests are placed in a large tree and built mostly of sticks

and other pieces of wood. Loss of habitat therefore, parti-

cularly cutting of big trees would affect the species. Like

sea eagles, the African Fish Eagle has structures on its

toes called spiricules that allows it to grasp fish an d other

slippery prey. The Osprey, a winter visitor to Africa, also

has this adaptation. Should the African Fish Eagle catch

a fish over 1.8 kg it will be too heavy to allow the eagle

to get lift, so it will instead drag the fish across the

surface of the water until it reaches the shore. If it

catches a fish that is too heavy to even allow the eagle to

sustain flight, it will drop into the water and padd le to the

nearest shore with its wings. So if the shore line of water

bodies is heavily settled by fishing camps as is usually

the case in Zambia, its feeding would be affected. Prey-

ing on domestic fowl (chickens), also causes conflicts

with humans and attempts to destroy fish eagles nests by

humans are on record (personal obs.).

2. MATERIALS AND METHODS

2.1. Location and Description of Study Area

The study was conducted in Lochinvar National Park,

Zambia which is 410 km2 in extent and is located at

Latitude 15˚43' - 16 ˚01' South, Longitude 27˚11' - 27˚19'

East and altitude of between 970 and 1038 m above sea

level.

About half of the area is pa rt of the Kafue flood p lain.

The Lochinvar National Park is on the south bank of the

Kafue River. Soils are dark grey and are of alluvial origin.

South of the flood plain, is a flat Terminalia zone on

sandy clay to clay soils which are water logged during

the wet season. Hot springs which are indicative of a

structural geologic fault occur where the woodlands meet

the southern boundary of the southern edge of Terminalia

zone. Average annual rainfall is 750 mm. Dominant grass

species on the flood plain vary. However, the most com-

C. Chomba, E. M’Simuko / Open Journal of Ecology 3 (2013) 325-330

327

mon species are: Oryza birthii, Vossia cuspidata, Echi-

nocloa stagnina and Panicum ripens. The commonest

herbs are Aeschynomone fluitans and Nymphaea capen-

sis. Steria sphacelata is the characteristic species in the

Terminalia grassland. This type of grassland is du e to the

high water table which is in this zone. South of the Na-

tional Park is a fire climax woodland of Aca cia, Albizia

and Combretum spp. In terms of large mammals, the

Kafue Flats in which Lochnivar National Park is lo cated,

has about 40,000 herds of endemic species of lechwe

(Kobus leche kafuensis), several thousands of other spe-

cies and has one of the largest concentrations of cattle in

the country. The Kafue River runs in between dividing

the Kafue Flats into North and South banks making it

suitable for this study as the fish eagle is at home with

fish in the Kafue River and lagoons while the white

backed vulture feasts on cattle and wild animal carcasses

(Figure 3).

the right hand side and two on the left hand side of the

transect. One carried a fire arm for the protection of the

research team against dangerous game such as African

buffalo (Syncerus caffer) and the other member was

navigating the transect to ensure that it is straight from

one end of the vegetation community to the other. About

17% of the National Pa r k was sampled.

The team members had a set of Garmin GPS 45 XL

each, for taking GPS locations of all trees with nests, a

pair of tasco 20 × binoculars for observing the species of

raptor on the nest, Bushn ell Yardage pro 500 range finder

to measure distance from the roads, park boundary or hu-

man disturbance where necessary, one tree height meas-

uring rod for measuring tree height, a 5 m steel tape for

measuring tree diameter at 1.3 m above ground, and a

canon power shot A 470 digital camera for taking pic-

tures of the nests, birds in the nest and other critical fea-

tures. Identification of trees with nests was done with the

aid of Tr ees of Southern Africa [4]. Identification of rap-

tors was done based on Oberprieler and Cillie’s raptor

guide of Southern Africa [5]. When a tree with a nest was

observed, a GPS location of the tree was taken, the tree

species name was identified and recor ded and the bird in

the nest identified and recorded as well. Tree height

2.2. Field Methods

The National Park was divided according to vegetation

communities. Line ground transects were used in both

wooded and flood plain habitats. A team of six resear-

chers walked along the transect. Two were observing on

Figure 3. Location of study area, Lochinvar National park on the Kafue Flats, Zambia 2012.

OPEN ACCESS

C. Chomba, E. M’Simuko / Open Journal of Ecology 3 (2013) 325-330

328

was then determined and DBH taken. Distance from the

park boundary was determined by the length of the tran-

sect and if the vegetation community was inside the Na-

tional Park, the remaining d istance was added. Since this

was the breeding season, it was expected that the nest

would have chicks or the parent would be present on

visit to the nest or incubating eggs. Five other visits were

made after the GPS locations were taken during the first

visit. Where no visits of the parents were observed or

chicks seen in the n est, an atte mpt was made to climb the

nearest tall tree from which we used a pair of binoculars

to see whether the nest was abandon ed or not.

An abandoned nest was relatively easy to tell as there

were no chicks in the nest, no parent brooding over the

eggs or bringing food to the chicks, it had no fresh drop-

pings on the ground, no fresh looking feathers which

often drop from the nest or some food remains which

may drop when the parent is feeding the young. Active

nests had all or most of these features.

Data collected were entered on data sheets and pic-

tures taken were downloaded at the base camp to verify

the species in instances where some times only the head

of the parent w as seen .

3. RESULTS

3.1. Selection of Tree Species for Placement

of Nests by Raptors

A total of 19 trees had raptor nests, of which 13 (68%

of total) had active nests and six (6) (32%) had aban-

doned nests. Of the 13 nests 8 (62%) were for White

backed vulture and 5 (32%) were for African Fish Eagle.

Of the 13 occupied nests, 8 (62%) were on Faidherbia

albida, 2 (15%) on Acacia xanthophloea, 2 (15%) on

Acacia nigrescens, and 1 (7.5%) on Albizia harveyii. The

difference in the placement of nests between tree species

was significantly different (



2, P < 0.05) in favour of

Faidherbia al b i da (Figure 4).

The mean height for the placement of nests in both

species was above 10 meters above ground. In African

fish eagle the mean height was 11.4 meters (n = 5) above

ground and 16.6 meters (n = 8) above ground for White

backed vulture .

3.2. Nest Placement with Respect to

Vegetation Community

Four vegetation communities were surveyed, Acacia

woodland, Mopane woodland, Shrubland, and flood

plain. Of the four vegetation co mmunities, 6 (46%) were

in Acacia woodland, 5 (39%) in Mopane woodland, 1

(7%) in shrubland, and 1 (7%) in flood plain. The differ-

ence in nest placement was found to be significantly dif-

ferent in favour of Acacia woodland (



2, P < 0.05),

(Figure 5).

3.3. Nest Placement in Relation to Distance

from Human Activity

Results obtained suggest that raptors avoided human

disturbance by abandoning nests. As reported above, the

total number of nests observed during the study was 19.

Of the 19 nests, 13 (68%) were occupied (active) and 6

(32%) were abandoned (inactive). Of the 6 that were

abandoned 5 (83%) were within 100 meters of human

disturbance near the park boundary, and 1 (7%) was near

the main road inside the National Park. All the occupied

nests were more than 100 meters away from human dis-

turbance or National Park boundary, suggesting that hu-

man encroachment and associated activities can impact

negatively on raptors by contriving them to abandon

their nests.

4. DISCUSSION

4.1. Selection of Tree Species for

Placement of Nests b y Raptors

Large trees are important for the two species of raptors;

first because the two species of birds are of large size and

construct large nests to support their weight and that of

their chicks. A highly placed nest also provides a vantage

point from which the bird can have a wide view to scan

the landscape for food.

It is also assumed that a highly placed nest would al-

low the nestling s to glide as they learn to fly. Such flight

requires horizontal movement of air over an aerofoil

surface. Perhaps it would also be easy for nestlings to

take advantage of thermals, a large vortex of sun heated

air to take flight [6]. Since raptor nests are made of dry

twigs and an assortment of pieces of wood, it would be

much safer to place a nest at a height which is out of

reach of dry season fires. Placing the nest at lower height

Acacia

nigrescens, 2

15%

Faidherbia

albida, 8

62%

lbizia

harveyi,1

Acacia

xanthophlea , 2

15%

Figure 4. Selection of tree species for placement of raptor nests,

Lochinvar National Park, Kafue Flats, Zambia, 2012.

C. Chomba, E. M’Simuko / Open Journal of Ecology 3 (2013) 325-330 329

y = -14.9x + 62

R2 = 0.864

Acacia woodland Mopane woodlandShrubland Flood plain

Vegetation community

Number; percent relative frequency

Number Percentage Linear (Percentag e )

Figure 5. Raptor nest placement with respect to vegetation

community selects, Lochinvar National Park, Kafue Flats,

Zambia, 2012.

would expose it to wild fires, implying that the eggs or

chicks would be destroyed by fire and the parents would

have to repeat the task of rebuilding a new nest and re-

investing energy in laying another clutch of eggs.

4.2. Nest Placement with Respect to

Vegetation Community

The Acacia and Mopane woodlands are the only vege-

tation communities in Lochinvar National Park with

large and tall trees which can accommodate raptor nests.

Since raptors require placing their nests at least 10 me-

ters above ground, they would only select vegetation

communities with large tall trees. Additionally, the

change in the flooding regime since the construction of

the Itezhi Tezhi dam in 1979 [7], has contributed to the

loss of some old trees and emergence of new secondary

vegetation communities which may not yet have large

trees suitable for raptor nest placement. The extension of

agricultural activities on the periphery of the National

Park coupled with charcoal production may have con-

tributed to loss of large trees in neighbouring vegetation

communities.

4.3. Nest Placement in Relation to Distance

from Human Activity

The Lochinvar National Park, on the Kafue Flats is a

source of fish protein from the Chunga lagoon and Kafue

River. Once or twice a week, the National Park authori-

ties permit fish traders to enter the National Park and buy

fish from fisher men on the shores of Chunga lagoon.

More than 30 pickup trucks each carrying more than ten

people which is a min imum of 300 p eople may enter the

National Park. Such large groups of people with the as-

sociated noise from vehicle exhaust systems and hooting

would disturb the birds. Anecdotal reports also indicate

that sometimes people stop to view raptor nests near the

main road, which due to their size is an attraction and

cannot be easily hidden from people’s view. The Kafue

flats is also home to more than 15,000 herds of cattle,

and every day herds men bring cattle into the National

Park for gr azing. Such human disturbances combined are

disruptive enou gh to force raptors to abandon th eir nests.

Frequent visits by humans and passersby in general may

reduce nest attendance by parents and may lead to the

nest being abandoned. There is also a belief that fish ea-

gle and vulture parts have magical and mythical powers

and many people would need them to be used as medi-

cine in magic spells. A nest for a vulture or eagle located

in an area that is not secured would definitely be a target

as people attempt to get at the parent bird or the chicks.

This observation is in agreement with an observation

made in Nigeria where vultures were caught and con-

sumed for perceived medicinal and psychological bene-

fits and the decline and possible ex tirpation in that coun-

try was attributed to the trade in vulture parts for tradi-

tional juju practices as indicated in [2] above.

5. CONCLUSION

After analyzing the data and testing the hypotheses, it

was concluded as follows:

1) Tall trees of the height exceeding 10 m are critical for

placement of raptor nests.

2) Human disturbance would lead to raptors abandoning

their nests and thereb y reducing breeding success.

3) Lochinvar National Park authorities should consider

zoning key breeding areas for raptors in the National

Park as low visitor use zones as frequent and unregu-

lated visitation may lead to nest aban donment.

4) Construction of roads and other facilities for man-

agement and visitor use should take into account the

need to maintain large trees for raptor nest place-

ments.

It was therefore, established that mature trees of more

than ten meters in height, located in areas with minimum

human disturbance are critical to successful breeding of

raptors on the Kafue Flats, Zambia. Opening of new

roads, construction of new buildings as well as increase-

ing human activities in such habitats may lead to raptors

abandoning their nests. New infrastructure in the Na-

tional Park should avoid areas with high density of raptor

nests as they are known to return to the same nest to lay

eggs.

6. ACKNOWLEDGEMENTS

We wish to thank the Regional Manager Mrs. Marina Sibbuku for

allowing the researchers to operate in the National Park un interrupted,

Ms Hellen Nkole Mwaba the area ecologist, for providing logistics and

participating in the exercise, Mr. Chaka Harold Kaumba for preparing

C. Chomba, E. M’Simuko / Open Journal of Ecology 3 (2013) 325-330

330

the map, Microsoft Incarta Encyclopaedia for the pictures for white

backed vulture and African fish eagle.

OPEN ACCESS

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