SynopsisThe estuary and Firth of Forth support an outstanding number and variety of wildfowl and waders at migration seasons and in midwinter. Although populations of wildfowl and waders fell from 25–35,000 and 50–65,000 respectively in the 1970s, to 10–15,000 and 30–40,000 by the mid-1980s, the Forth remains one of few British estuaries to support more than fifteen waterfowl species of national importance for conservation. The ecology and decline of diving ducks off Edinburgh and population studies of shelduck have been given particular attention by researchers. Among waders, distributions, movements and feeding have been studied in detail. The causes of the recent declines amongst waders, notably for knot (Calidris canutus) and dunlin (Calidris alpina) on the estuarine Forth, remain uncertain, but are likely to include natural factors as well as those linked to man's activities.