BOSTON >> Never mind the robins. The real harbingers of spring, Canada's "ice seals," are returning to the Massachusetts coastline.

Naturalists say young harp seals and adult hooded seals have been spotted from Cape Ann to the South Shore.

The animals are known collectively as ice seals because they swim south from the ice fields of Canada's Maritime Provinces to take a break in comparatively balmy New England. Experts say the migration has been happening for about two decades.

Marine animal rescuers from the New England Aquarium responded to calls for help this past week in Marblehead, Nahant and Norwell, where juvenile seals came ashore.

Biologists say just because a seal is on the beach doesn't mean it's stranded. They're reminding the public to keep their distance and ensure dogs are leashed.