Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No 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.
Beginning in April, females and young migrate northward from breeding areas in the Bering Sea into the Chukchi Sea following the retreating sea ice. Some individuals probably migrate more than 3000 km in a year, some or much of which may be done on floating cakes of ice (Reeves et al. 1992). Some sub-adult males make the northward migration along with the females. Along the Alaskan coast, small numbers of adult males apparently also make the migration following several weeks behind the majority of females. Mixed herds of males and females haul out at select locations along the Chukotka Peninsula and Wrangell Island, Russia in the summer months. Return migration commences in late September as sea ice advances southward. The majority of males stay in the Bering Sea throughout the summer making use of haulouts in Bristol Bay, Alaska, and along the Koryak coast in Russia (Fay 1985); similar seasonal movement may occur in North Atlantic.