Movements of wintering shorebirds within the Firth of Forth: Species differences in usage of an intertidal complex

The movements of seven species of waders within and through the estuarine complex of the Firth of Forth, Scotland, were studied by dye-marking and ringing in three winters, 1978–1981. The species studied formed two groups (which may be part of a continuum). Grey plovers Pluvialis squatarola, turnstones Arenaria interpres, oystercatchers Haematopus ostralegus and redshanks Tringa totanus tended to stay within the same part of the estuary throughout the winter. Bar-tailed godwits Limosa lapponica, dunlins Calidris alpina and knots C. canutus ranged more widely. Knots dispersed rapidly throughout the whole of the Firth, and probably elsewhere. Retraps of ringed birds indicated year-to-year differences broadly similar to the within-winter ones. The results are compared with data from elsewhere, and are discussed in relation to large-scale reclamation proposals for the Forth.