Ichkeul is a lake that behaves like a lung. In winter it fills with fresh water from the rivers of northern Tunisia, and thousands upon thousands of ducks, geese and coots arrive from Europe, making it one of the great wintering grounds on the migration route between the continents. In summer the sea creeps in from Lake Bizerte through a channel, the water turns brackish, and the birds leave. That seesaw between fresh and salt is the heart of the place, and UNESCO listed the national park in 1980 for its importance to waterfowl. The Tunisian state's dams on the feeding rivers have put the balance under strain, which is a story the park authorities have been wrestling with for years.
Rising from the southern shore of the lake is Jebel Ichkeul, a limestone ridge that stands at around five hundred metres, with old olive and carob trees on its slopes and raptors turning overhead. Down at its foot there is a small information point for visitors. Water buffalo, brought long ago, graze the shallow edges, which is unexpected in North Africa.
The ride in is quiet and very Tunisian. From the road between Bizerte and Mateur you pass through farmland with olives, wheat and artichokes, and the roads are usually decent but narrow, with donkey carts, scooters and overloaded vans. Spring is superb, when everything is green and the flowers cover the slopes, while from midsummer onward the heat flattens everything. Winter is the time for the birds, but also for rain and mud on the tracks around the lake.
Mateur, Menzel Bourguiba and Bizerte all have fuel and cafes, so fill up before heading into the park, which has little in the way of services. Bring water, and ask at the entrance about walking the mountain track, as access and opening times can change.
Behind all this sits a larger story. This part of Tunisia was Carthaginian, then Roman, and the great ruins of Dougga lie a morning's ride away to the south. It would be a mistake to treat the lake as only a bird sanctuary.