Eygenraam J.A. (1957) The sex-ratio and the production of the Mallard, Anas plathyrhynchos L. ARDEA 45 (3-4): 117-143

1. The Mallard's production was investigated by counts of Mallard broods, the location, date, number and age of the ducklings being noted. 2. The hatching dates were inferred from the data, and a maximum for the hatching of young was found in the first decade of May. 3. The average number of ducklings reared by a successful female is fairly constant and amounts to six. 4. The percentage of ducks that are unsuccessful in rearing young is probably variable, and was 23 and 24 in 1953 and 1954 respectively. 5. This percentage must be subtracted from the figure of six in order to arrive at the reproduction figure. 6. Judging from the average decoy catches in September these were by no means favourable years. 7. The nesting population may be estimated at 300,000 Mallards, including 145,000 females. These rear an average of five ducklings, so that the annual production should be put at 725,000.