As freezing autumn winds begin to whistle into Europe from the north, a host of migratory birds are thinking of more hospitable climates to the south and start on their long annual excursion. After braving the obstacles of southern Europe, where every bush seems to hide a hunter with a shotgun, navigating the featureless Mediterranean Sea, and transversing the arid Sahara, the birds arrive at their first oasis: Djoudj National Bird Sanctuary.
Located in the delta of the Senegal River, near Senegal's border with Mauritania, Djoudj covers some 16,000 ha of river channels, backwaters, streams, ponds and a large lake (which covers about a quarter of the sanctuary). In addition, the waters also hold populations of crocodile and African manatee, and the forests and grasslands hold species typical of the Sahelian zone of Africa.
The park is in a vast basin of impermeable halomorphic soils forming saline flats in the Senegal River Delta between the main channel to the north, the Djoudj bayou and the Gorom, or bayou to the south. This delta, of which Djoudj is a small part, has been subject to flooding and to the development of dyke systems for many years, the latest in 1963. These dykes have allowed the retention of fresh water in the Djoudj basin longer than normal, which benefits the water birds. Salinity varies, from almost fresh during the winter inundations to brackish as the water levels fall.
Vegetation reflects low rainfall. The Sahelien type savannah is dominated by spiny bushes, acacias, tamarisk and Balanites aegvptiaca . During the rains, dense populations of Typha and water-lily species appear in the flooded zones. Halophytic plants cover much of the area.
The park was mainly established as the area is so important for birds, supporting 3 million waterfowl, and is one of the main West African sanctuaries for Palaearctic migrants. It is one of the first fresh water sources they reach after crossing 200 km of the Sahara. From September to April, an estimated 3 million migrants pass through, including garganey, shoveler, ruff, pintail and black-tailed godwit. Thousands of flamingo nest here regularly as well as 5,000 white pelican, white-faced tree duck, fulvus tree duck, spur-winged goose, purple heron, night heron, various egrets, spoonbill, African darter, common cormorant and Sudan bustard. Mammals include warthog and West African manatee, and several species of crocodile and gazelle have been successfully reintroduced into the area.
But this wildlife haven is threatened from many sides. Agricultural chemicals are finding their way into the once-pristine waters of the Senegal River thus disturbing delicate links in the food chain, and a dam is being built which will disturb the annual wet-dry cycles that have brought life to Djoudj. A study sponsored by the World Heritage Committee has reported on the measures required to ameliorate the effects of the dam through an inexpensive series of dikes and sluice-gates and a carefully timed release of the life-bringing waters. It is hoped that the World Heritage status of Djoudj will help convince the government of Senegal to take the necessary measures.