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A wild dabbler
Also known as « the green-headed » or Colvert duck, the Mallard is the most widespread of wild ducks. It can be found almost everywhere in the world. It nests in Europe, North America and Asia, in wetlands such as marshes, large and small lakes or calm rivers.
The mallard belongs to the family of surface-feeding, or “dabbling” ducks, advancing over the surface by making alternate circular movements with its feet. Indeed, it spends a large part of its time on the water, going onto dry land only to nest or to rest.
It is mainly vegetarian, feeding on a variety of seeds. It also eats molluscs, insects, small fish, tadpoles, snails and fish eggs. Its fishing technique : it plunges its head in the water and tips forward, so that it can reach the bottom with its beak.
Living on its reserves
After a period of too-severe food restrictions, certain birds do not manage to reconstitute their energy reserves. They continue to lose weight despite starting to feed again. Scientists from the multi-disciplinary Hubert Curien Institute have discovered a blackish substance they call « intestinal tar», in the intestines of these birds.
The teams studying this phenomenon thought at the time that the presence of the tar revealed an irreversible deterioration of the digestive system. However, Mallards in a situation of prolonged starvation that is still reversible, also produce this substance.
This « intestinal tar » therefore appears during a period of starvation and might even correspond to an ultimate process of adaptation prior to the situation becoming irreversible. To elucidate the mystery, further in-depth studies are planned in collaboration with the Union Française des Centres de Soins and the Paul Emile Victor Polar Institute.
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