She incubates for 33-35 days, leaving the nest only for short periods to forage. The male swims nearby, guarding against predators. Fluffy pale gray down covers the newly hatched cygnets. They leave the nest after a day or two to begin to feed themselves. The parents help them by breaking plant material off so that it floats to the surface where the buoyant youngsters can reach it.
Many cygnets succumb to cold, wet weather, parasites, insufficient food, or predators.
It is normal for each family to lose nearly half of the clutch. The first feathers emerge after one month, and at 10 weeks they are fully feathered in a light brownish-gray. By 15 weeks, they have reached a weight of 9 kg and are learning to fly. Northern breeders have very little time to perfect flight before they must leave the rapidly freezing lakes for wintering grounds. Prior to the 19 th century Trumpeter Swans were fairly common all across the northern prairies.