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.