The whales are now on the final stretch of their journey, with Nigel accompanying them all the way to the Bering Sea.

As the whales swim further into the cold seas of the Pacific Northwest, Nigel joins the Quileute tribe for their annual whale-welcoming ceremony.

Nigel Marven follows the grey whales up the Californian coast, spotting humpbacks, a unique fox and Californian condors en route.

In Baja California in Mexico, newborn grey whale calves spend their first months of life in the safety of the San Ignacio lagoon.