Common Shelduck - a Sea Duck for the Back Yard

Abstract

Of the world's waterfowl, those species living in northern oceans capture the imagination with their bold or unusual colors and patterns, interesting shapes, and specialized natural histories. For the most part, however, maritime ducks and geese have traditionally been avicultural subjects only for the advanced collector. Eiders, Scoters, Harlequins, and the Oldsquaw or Long-tailed Duck require specialized diets and care, and are mostly very difficult to come by. Brant Geese, Canvasbacks, Goldeneyes, and Buffle-head accept more routine conditions and are commercially available but are, in most cases, costly. There is one duck of the northern seas, readily available and easy to manage, a bird of magnificent appearence; the Common Shelduck (Tadorna tadorna).

The Common Shelduck, also known as the European or Northern Shelduck, breeds only along coastlines, inland seas or salt lakes (Delacour-1954, Johnsgard 1978), with only some migrating populations occurring in freshwater. Along the coast of Europe, the breeding range extends from France to Norway, including the southern Baltic shore, east to Estonia (Johnsgard 1978). The Mediterranean breeding range is restricted to Spain, the famous Camargue of France, Sardinia, Tunisia and the Balkan Coast (Delacour, 1954, Johnsgard 1978). Common Shelducks also breed on the northern shore of the Black Sea, and a separate Asian population nests around the Caspian Sea and the salt lakes of Central Asia, east to North China and Tibet (Delacour 1954). The northern European population is basically resident year around - migration occurs in July, just before the molt. Ninety percent of these western birds molt at Great Knechtsand, in Heligoland Bight, off Germany (Johnsgard 1978, Kolbe 1979). The North Sea birds do not usually go south for the winter. The continental population winter on North Sea mud flats. Only '' periods of severe frost" send them to Britain, or occasionally south to Portugal (Kolbe 1979). British birds molting in Heligoland return to the British Isles and winter there (Delacour 1954). Mediterranean birds do winter in north Africa and Egypt, while the Asian population migrates to northern India, Northern Vietnam, Myanmar, China, and Japan (Delacour 1954).

The primary food of the Common Shelduck is mollusks. The northern European and British birds subsist largely on the mud flat snail Hydrobia (Johnsgard 1978). Fish, fish eggs, other invertebrates, and marine algae make up a smaller proportion of their diet. The preferred nest site is a rabbit burrow (Kolbe 1979). Nests may otherwise occupy other holes in the ground, hollow trees, or rarely between rocks or in heather. Breeding commences in the spring.

Jean Delacour (1954) writes that the Common Shelduck has '' long been kept in captivity in Europe". How long may be gathered from a couple of illustrations in A History of Domesticated Animals, by Frederick Zuener (1963), Professor of Environmental Archaeology at the University of London. On page 471, a beautifully detailed Common Shelduck and Common Teal (Anas c. crecca) appear in a Roman mosaic in the collection of the National Museum at Naples. Although this pair is sitting on a table with shellfish and fish for dinner, they are obviously life studies. Professor Zuener mentions that the Romans kept wild ducks in enclosures called Nessotrophia. While the Naples mosaic is not dated, the delightful one from Pompeii, on page 405, was obviously created before that city was entombed by the erruption of Mount Vesuvius in 79 A.D.