08.09.2021 – Time on the water

We owe a lot of the successful sightings to the activity of marine birds out at sea and particularly rely on the activity of Cory’s shearwaters (Calonectris borealis) at sea. Cory’s belong to the family of the Tubenoses (Procellariiformes), an order of seabirds that includes storm petrels, petrels, shearwaters and albatrosses. These colonial birds have a strong connection to their birthplace and return to their natal colonies to have their young once they’ve matured, a phenomenon known as philopatry. The birds only have one chick a year and, while one of the parents tends to the chick, the other spends the entire day out on the Atlantic to forage for its family. As they forage, Cory’s and other birds often follow cetaceans or other predators for hunting advantages and therefore act as our little helpers when it comes to finding cetaceans at sea.

With the help of the birds both our boats were able to find a group of shy Striped dolphins (Stenella coeruleoalba) and our Stenella even managed an extremely brief sighting with beaked whales, probably Cuvier’s beaked whales (Ziphius cavirostris). Now beaked whales aren’t usually marked by bird activity since they spend most of their time in the deep where they also forage, giving the birds absolutely no hunting advantages. Todays smooth conditions enabled the sharp eyes of our spotter and crew at sea to find these animals and both our boats managed another beaked whale encounter this afternoon, this time with Blainville’s beaked whales (Mesoplodon densirostris). Our zodiac ventured further east and far offshore to meet some Atlantic spotted dolphins (Stenella frontalis) and an unknown baleen whale species (Balaenopetera) and both species were marked by some active Cory’s.

At the end of the day our sightings depend on efficient teamwork but we are also immensely grateful to have the help of these charismatic seabirds. After all, they do spend more time on the water than we do in a day, so we have every reason to trust them.

By Paula Thake

Sightings of the day

Ribeira Brava

10:00 Striped dolphins

15:00 Blainville’s beaked whales

Stenella

09:30 Cuvier’s beaked whales, Striped dolphins

14:00 Blainville’s beaked whales

17:00 Atlantic spotted dolphins, Baleen whale