The Large pond is a famous historical place of the Moscow zoo where a great number of waterfowl birds is exhibited. It has been saved since 1864. In 1996 the large pond was cleaned and a new special aeration system was established. In winter powerful compressors save non-freezing ice-holes where birds may swim. Only heat-loving species are transferred to warm enclosures.
Trumpeter swans and swan geese are kept in the large pond all the year round. These species are very rare in the wild and they are listed in the Red Book IUCN.

The trumpeter swan (CYGNUS CYGNUS BUCCINATOR) (ANATIDAE) occurs in the northern regions of USA and Canada. It is the largest swan with a very loud voice At the age of three years young trumpeter swans form permanent pairs. As other swans they actively protect the territory near their nest. Nests are large, about 1,5 meters in a diameter. Females usually lay from 3 to 7 eggs, hatching lasts about 7 weeks.
In recent times trumpeter swans had been exterminated almost in all parts of area because the species was intensively hunted. In 1933 there were only 33 birds in USA. Now the species is protected by the law and as a result the wild population is estimated to number 5000 pairs. In the Moscow zoo trumpeter swans breed every year. The group consists of 7-10 birds.

In Russia the swan goose (ANSER CYGNOIDES) (ANATIDAE) nests in Priamurie and Zabaikalie, and also occurs in eastern Kazakhstan, Mongolia and northeastern China. They inhabit bogs forest lakes and rivers in mountains with scarce vegetation around. Clutch size is 5-6 white eggs. Hatching is female's duty while male usually defends the nest. Swan goose swims and dives excellently. In moult time in danger it submerges under the water so, that only a head is visible, or completely disappears under the surface. The diet consists of green parts of plants. Swan geese are easily tamed. Every year 33-35 birds inhabit the Large pond where they regularly breed.

Mallards (ANAS PLATYRHYNCHOS) and ruddy shelducks (TADORNA FERRUGINEA) (ANATIDAE) are the most numerous free living ducks in the Moscow zoo. In winter their flocks occupy non-freesing patches of the ponds and in spring they disperse to their individual home ranges.
Bright ruddy shelducks frequently nest on the adjacent to the Zoo houses where they build their nests in garrets. In June one can see the nestlings, covered with dense downs, falling from the height on the ground, like small parachutes. Then both parents lead them to the zoo pond.