Females have been seen breeding with three males in 45 minutes. Northern migration By March, whales are already returning northward along the Oregon Coast. These animals pass the Oregon coast from early March through April. Breeding sometimes is observed at this time. Calves usually are rambunctious but stay close to their mothers as they become more coordinated and develop an insulating blubber layer.
Calves are at least a month old before they migrate north with their mothers.
Mothers and calves are the last t leave the lagoons and move somewhat more slowly, passing Oregon and Washington from later April through June. During the spring migration, if the weather is good, you can see whales within a few hundred yards of coastal headlands. Other whales also are known to migrate between summer high latitude feeding grounds and more temperate low latitude breeding and calving areas. However, researchers known more about the gray whale because it moves so close to shore. This near-shore movement has led to speculation that gray whales navigate by staying in shallow water or keeping the surf noises to one side or the other depending upon their direction of travel.