The narrow channels and lakes behind the main arms are the productive water. Great white and Dalmatian pelicans — the delta holds the largest pelican colonies in Europe — fish in coordinated groups, with pygmy cormorants, glossy ibis, squacco and purple herons in the marginal vegetation.

The reedbeds, which cover much of the delta and form the largest continuous reed area on Earth, hold bitterns, marsh harriers quartering low, and a chorus of warblers. Floating reed islands drift and reshape the channels from year to year.

Letea and Caraorman forests, on ancient sand dunes within the delta, are startlingly different — oak woodland with lianas, white-tailed eagles nesting, and semi-wild horses that have become an attraction in themselves.

The lagoons near the coast hold terns, waders and, in winter, red-breasted geese — a globally threatened species that winters here in internationally important numbers.

April to June is the peak: breeding plumage, pelican colonies active, and the reed alive with birdsong. Autumn migration is excellent and quieter; winter is harsh but holds the geese and, sometimes, ice.

Practicalities

Tulcea is the main gateway, reached by road from Bucharest in about four hours, with ferries and boats into the delta from there. Sfântu Gheorghe, Crișan and Mila 23 are the villages to stay in for early starts.

Hire a local boatman rather than joining a large excursion — the difference in wildlife is enormous, and the delta's fishing communities depend on this work. An entry permit for the biosphere reserve is required and is usually arranged by your host or boatman.