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RADAR TRACKS OF PALAEARCTIC WADERS DEPARTING FROM THE COAST OF GHANA IN SPRING
Authors:L. G. Grimes
Affiliation:Physics Department, University of Ghana, POB 67, Legon, Ghana
Abstract:During the northern spring of 1970 and 1971, wader departures were tracked by radar from saltpans on the coast of Ghana near Accra. All but one of the departures headed northeast, and none were directed along the coast. There was a statistically significant difference between the mean heading of April departures (28°± 10°), and May and June departures (41°± 14°). Projected on great circles, all headings were directed towards the known breeding ranges of the wader species wintering at the saltpans.
In ten species, the dates of the first returning birds to the saltpans in 1966, 1968 and 1970 were about three weeks earlier than dates recorded in Senegal. It is likely that those reaching Senegal follow a coastal route, whereas waders wintering at the coast of Ghana and eastwards to Nigeria evidently make a crossing of the Sahara both in autumn and spring.
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