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Résumé :
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A method is described of obtaining indices to represent the relative abundance of ducks in the same m onth of different years and in each season as a whole. Results are based on the sample which has been used since September 1959 to produce m onthly reports for observers in the National Wildfowl Count Scheme. The species investigated are Tufted Duck, Pochard, M allard, Teal and Wigeon, and the months under consideration September to M arch inclusive. The period covered is from autum n 1948 to spring 1960.
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