50) THE WATTLED CRANE
The wattled crane, largest of Africa's cranes is also the rarest,
numbering 10 000 birds at most.
RANGE AND HABITAT
Within southern Africa the wattled crane has a fragmented range.
One population extends from Natal to the eastern Transvaal and
Swaziland. A second population occurs in the Zimbabwe highlands.
All these birds are more or less resident and inhabit permanent
wetlands. Other populations are nomadic. The wattled cranes of
Bushmanland in Namibia and Botswana inhabit seasonal pans and
temporarily flooded areas, moving on during dry periods.
Recently 2570 wattled cranes were counted in the Zambezi delta,
although their status (nomadic or resident) is unknown.
LIFE HISTORY
Wattled cranes breed only in wetlands. Breeding pairs maintain
a territory, so that nests are always at least 500m apart. The
nest is a large mound of grasses and sedges placed on a tuft,
surrounded by open water. One or two eggs are laid, but only one
ever hatches, the other being abandoned. This seems wasteful,
but if wattled crane chicks are put together they fight to the
death. Laying the second egg is probably insurance against the
first failing to hatch.
The little chick is covered in yellowish down and looks rather
like a duckling. It can walk and swim straight away, and follows
its parents closely. They teach it to feed on bulbs, corms and
insects by probing into the soft surface of the soil. If danger
threatens the chick hides under a grass tuft and the parents walk
away to distract the intruder. The chick grows rapidly, and is
as tall as its parents at three months, and can fly by four
months. It stays with its parents until they are ready to breed
again, when they drive the chick away.
Not all chicks survive, and many hazards await them. Even before
an egg hatches it may be lost to a predator. After hatching the
chick is vulnerable to fire, for the nesting peak is in mid-
winter when grass fires are frequent. Even older chicks are at
risk and can be killed by hail. Only about one brood in three
produces a fledged chick.
Young birds have full adult plumage at one year, but only become
sexually mature at 4-8 years. Prior to sexual maturity they form
roving flocks which are not confined to wetlands. These flocks
forage on grainlands where they feed on harvest leftovers, often
in the company of blue and crowned cranes. This is where cranes
sometimes get poisoned, either taking in pesticide residues, or
eating poison laid deliberately. In some areas cranes are seen
as crop pests, in others as an easy source of food.
Wattled cranes can look forward to a long life once they have
achieved maturity. The average life-span is 20-30 years, with
a maximum of at least 80.
WATTLED CRANE RESERVES
Wattled crane numbers are low and their habitat is threatened.
The permanent wetlands of the highlands are scattered and
difficult to consolidate into reserves. The two most important
reserves created specifically for wattled crane are Verloren
Valei in the Steenkampsberg, Eastern Transvaal, where up to
twelve pairs nest, and Umgeni Vlei in KwaZulu/Natal where ten
pairs nest.
AGRICULTURAL THREATS
Most permanent nest sites are in private hands and are at risk
from the following:
* damming of rivers to provide trout fishing or water for
irrigation;
* drainage of wetlands to provide grazing or arable land;
* timber plantations in the catchment area - timber uses much more
water than the grassland that it replaces, so rainfall run-off
into wetlands is reduced and eventually they dry up.
Loss of nest sites for these reasons can only be prevented by
proper protection from an informed and concerned farmer.
INDUSTRIAL THREATS
Demands on water, as these affect wetlands, threaten wattled
crane everywhere: In Botswana nesting opportunities may be
reduced if the waters of the Okavango Delta are tapped for that
country's diamond industry. In Zambia a hydro-electric scheme on
the Kafue River is controlling floods and reducing nesting sites
for wattled cranes in the area. If these wattled cranes are to
survive, provision must be made for them in future industrial
plans.
WHAT YOU CAN DO
* Adopt a wetland. Even if no wattled cranes live there, it is
valuable piece of a disappearing habitat. By learning about it,
and drawing attention to wetlands you will help to save all
wetland inhabitants.
* Never disturb breeding birds as this may cause them to leave
their nest.
* If you have cranes, especially wattled cranes on your
property, report their presence to the SA Crane Foundation.
* Support the SA Crane Foundation.
FURTHER READING
ROBERTS' BIRDS OF SOUTH AFRICA.
G.L. Maclean. John Voelcker Bird Book Fund, Cape Town, 1985.
SOUTHERN AFRICA'S THREATENED WILDLIFE.
J. Ledger. Endangered Wildlife Trust, Johannesburg, 1990.
Enviro Facts: "Wetlands"
USEFUL ADDRESSES
The International Crane Foundation.
E-11376 Shady Lane Road, Baraboo, Wisconsin, 53913, USA.
The Southern African Crane Foundation.
PO Box 3316, Durban, 4000. Tel. 031-233041
The Endangered Wildlife Trust.
Private Bag X11, Parkview, 2122. Tel. 011-4861102.
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