The food and feeding-habits of the Pochard, Aythya ferina
The food and feeding habits of Pochard (Aythya ferina) are described, based on stomach analyses of 45 birds collected between 1st September and 31st January, on field observations, and on a survey of the literature. Pochard feeding inland were found to have fed mainly on Chara and Nitella species, and to a lesser extent on Potamogeton and Polygonum species, as well as on larvae of Chironomidae. A survey of the literature substantially agrees with these results. Pochard feeding in coastal areas, including brackish water situations, are likely to have been feeding on Ruppia and Zostera species, and probably also on various Mollusca. Information is given on feeding behaviour, with observations on the daily activity of Pochard, the methods of feeding, and the times and depths of diving. Changes in the distribution of wintering Pochard in Britain are described and related to changes in environment, e.g. drainage schemes, decrease in Zostera, new reservoirs, and gravel pits. The paper illustrates the need for up-to-date work on the Pochard, and how necessary it is to have particular knowledge of the bird's feeding behaviour and diet preferences when formulating conservation projects.