Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.
Extent of southward migration may depend on winter temperature, water conditions, and population size. Arrives in northern breeding areas in late March and early April, in far north from mid-May into June. Departs from northern breeding areas late September into November (may depart from far north by mid-August) (Palmer 1976).
Makes postbreeding migration to molting area; females that nested in Suisun Marsh, California, began leaving in late May, 50% had departed by mid-June, and nearly all had departed by mid-July; migrated mainly northward to areas in California and south-central Oregon, 12-536 km from nesting sites; exhibited fidelity to molting area (Yarris et al. 1994).