Why are Trumpeter Swans nocturnal?

Premise is Incorrect: Trumpeter swans are not nocturnal species. Trumpeter swans are diurnal birds, which means they are most active during the daytime. They typically start their day at sunrise and are most active in the morning and late afternoon hours. During the night, swans sleep in water or on land close to water bodies. Their primary periods of activity coincide with feeding, and most swans rest at night.