Turnover in the Population of Ruddy-Headed Geese (Chloephaga rubidiceps) at Goose Green, Falkland Islands

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Abstract
(1) One hundred and eight-five ruddy-headed geese were marked when moulting at localities near Goose Green settlement, and individuals were subsequently recorded together with counts of the total population at the settlement, in order to estimate turnover in the ''pool'' of birds which used Goose Green as a feeding site. (2) The population at Goose Green settlement was largest in autummn after the flightless moult, smaller in winter and at its lowest level in spring and summer when breeding and moulting occurred. A small peak occurred in December prior to the moult. (3) Average turnover of about 18% per month was estimated for the period after the completion of moult in January, through until August in 1979 and October in 1980. Thereafter, until the end of the year, marked geese started returning to Goose Green, indicating fidelity to this site. (4) Estimates of the size of the ''pool'' of birds at Goose Green ranged from 381 to 813 (excluding two unreliable estimates), but were mostly around 500 birds. (5) Resightings of marked individuals outside Goose Green settlement indicated that birds travelled up to 30 km from the settement, though most re-sightings were within 5 km. (6) The high rates of turnover at feeding sites tend to nullify the effects of culls by sheep-farmers who try to reduce numbers of geese feeding on valuable crops or pastures.