In the far south of Morocco, between the Atlantic Ocean and the Sahara Desert, Khnifiss lagoon is a stopover for thousands of migrating pink flamingoes, which is likely to extend the limits of the tourist circuit.

A saltwater inlet, several hundred meters wide and separated from the coast by about 20 kilometers of sand dunes, the lagoon is home to almost 180 species of sea birds and waterfowl such as snipe, spoonbills and sanderlings, best seen along its mudflats at low tide.

The sandbanks also house a variety of seagrasses, shellfish and small mammals, while inland a row of 50-meter sandstone cliffs contain prehistoric sites where carved flints and ostrich eggs have been found.

But the real stars of the lagoon are the pink flamingoes. The great birds can be found there all year round, but the best time to see them in large numbers is winter, when up to 1,000 fly north from Senegal to Khnifiss, one of the very few wet ecosystems on the edge of the Sahara.

Because of its remarkable ecological diversity, the lagoon has been designated as a permanent nature reserve by the Moroccan government and is recognized as a site of world importance by Birdlife International.

For the present, however, it is so far off the beaten track for tourists and receives so few visitors that those who venture out onto the water in a fishing boat can easily approach the birds.

At the height of the migration season, up to 20,000 birds gather in the area, some of which stay to breed.

Essaid Makkak, regional director of the government's Department of Water and Forests, said a project to make Khnifiss a national park was officially approved last month and is likely to get off the ground later this year.

However, the ecology of the lagoon is fragile - its mouth silted up after being used by the Portuguese as a port in the 16th century - and the authorities are anxious to ensure that any development is sustainable.