Mongolia has over 11 extensive regions with plenty of water resources covering a total area of almost 3,700,000 acres. The lakes play a fundamentally important role in supplying the country's ground water needs. Vast reed beds and extensive aquatic plant communities provide a suitable habitat for a large number of breeding and migratory water birds. There are 18 species of birds included in the Mongolian red data book. One of them is the mute swan (cygnus olor). This swan breeds in sub-arctic and taiga habitats of Eurasia which extend as far as Mongolia in the Far East. On average they lay five eggs, each weighing around twelve ounces. The incubation period is 31 days and the grey cygnets weigh seven to eight ounces when they hatch. At up to thirty pounds, adult whooper swans are among the heaviest of all migratory birds. Even so, they can travel at speeds in excess of fifty-five miles per hour. This Bank of Mongolia issue displays a mute swan in a typically Mongolian lake district. The silver coin also features a very special addition in the form of the flower of the water lily, itself a Swarovski component.