Sooty Shearwaters

Massive schools of anchovies have encroached upon Santa Cruz Harbor — and they’ve attracted impressive numbers of Sooty Shearwaters!
From Julia Gaudinski of Mobile Ranger:
We are lucky in Santa Cruz to get visited annually by sooty shearwaters (Puffinus griseus) as they make their spectacular circum-global migration of 40,000 miles: the longest recorded migration of any bird. Each year, they spend about 5 months breeding and rearing their young and the rest of the year they are migrating!
All sooty shearwaters breed on small islands in the south Pacific and south Atlantic Oceans, beginning in October. Their population is estimated at well over 20 million. They incubate their young for 2 months, and raise their chicks for 3 months. They then fly north up the western side of the Pacific and Atlantic Oceans in March–May. They reach sub-Arctic waters in June–July where they cross from west to east and return south down the eastern side of the Pacific or Atlantic Ocean in September–October. All to arrive back at their breeding colonies and start the process over again.
Amazingly, they do not migrate as a flock, but rather as single individuals. They associate in groups only as the opportunity arises. When they are here you can see them stream by in what seems like an endless chain.
It was once thought that the migration was a fairly neat figure eight, with each bird covering the entire Pacific Basin from the Alaska area to the Antarctic. Now, thanks to electronic tagging research done in the mid-2000s, we know this is not true. Instead, individual birds go to either, Japan, Alaska or California and stay there until it is time to return south to breed.
This work also shows that the birds that travel to different regions do not represent distinct shearwater populations; two birds from the same nest can end up going to opposite sides of the Pacific, and birds from different breeding colonies can end up in the same place.
The “sooty” part of the name is appropriate as the entire bird is a dusty, dark ash-gray color. They have long narrow wings with a silver sheen on the under-wing. The bill is also dark and has what looks like two short pieces of soda straw attached to the top near the head. These “straws” are highly sensitive to the smell of fish, squid, and krill: their main food. The “shearwater” part of the name comes from their flying style: a few fast flaps followed by a stiff glide just inches above the water.
Like the content? Please like our page and check out our mobile AppTours that feature the natural and human history of the Santa Cruz coast. One of which is free!

Video- Archer Koch

Music: Hydra by Huma-Huma

Leave a Reply