The humpback whale is a migratory species feeding from spring through fall in high-latitude nutrient rich waters. In early winter they migrate to sub-tropical and tropical waters for calving and breeding. They do not feed during this winter migration. Every fall we know that one by one they will slowly begin their annual migration south.
The first to leave are mother and calves, then sub-adults then adult males. The last whales to leave the feeding grounds are the pregnant females. They will need every ounce of nutrition to sustain them during the rigors of the long migration, birthing and then nursing their calves. There is no food available for these mothers in the calving grounds and they will not forage their next meal until travelling northwards again, this with a calf by their side.
Some of our resident humpback whales migrate to a group of islands east of Japan. Another group makes the long voyage to Baja and Hawaii. The migration will take from 4 to 8 weeks. The estimated distance each way is 3000 miles, which is one of the longest known migrations of any mammal. However, we now have reports of humpback whales that do not migrate at all, and remain resident to this area for the entire year.