The breeding pairs maintain territories throughout nesting and brood-rearing. Both parents guard the cygnets until they fledge just before fall migration. The cygnets stay with their parents until they have returned to the coastal plain the following year. During summer, non-breeding birds move around locally, usually in lines low over the tundra. They sometimes form larger flocks to feed and rest, or search for places to do so.
Tundra swans feed on the stems, seeds, roots and tubers of submerged and emergent aquatic plants.
Just before fall migration, the swans gather along the brackish shorelines of river deltas to rest and feed. In September they depart the coastal plain in flocks of family groups and non-breeding birds. The swans migrate, with others from northern Alaska and northwestern Canada, across the continent to wintering areas on the Atlantic coast from Maryland to North Carolina. The arctic wetland habitats and quiet solitude of the coastal plain are critically important to the successful breeding of tundra swans on the Refuge. The birds are an indicator of the health and productivity of the coastal plain ecosystem.