It is joined by four main tributaries, the Drina, Bosna, Vrbas and Una.
The Drina is formed on the Montenegrin frontier by the united streams of the Tara and Piva; curving north-eastwards past Visegrad, it marches for 102 m.
Snipe, woodcock, ducks and rails, in vast flocks, haunt the banks of the Drina and Save; while the crane, pelican, wild-swan and wild-goose are fairly plentiful.
Small steamers ply on the Drina, Save and Una, but the Bosna, though broad from its very source, is, like the Vrbas, too full of shallows to be utilized; while the Narenta only begins to be navigable when it enters Dalmatia.
Ban, each designated by the regional name (Danube, Morava, Drina, Shumaja, Timok and the Ban numeral, e.g.