A mute swan lays a clutch of six eggs on average, but 11 is not uncommon. The lightly colored eggs vary from off-white to pale green. One egg is released daily; 35 days later the eggs hatch, and gray or white cygnets emerge.
At 6 months, cygnets begin to fly and are considered juveniles. Approximately three cygnets in the clutch survive to become juveniles. The most common causes of death are starvation, collisions with structures, such as bridges, and diseases, such as lead poisoning. Despite their name, mute swans do communicate with grunts, snorts and hisses, especially when disturbed or threatened.