Wildlife Spotlight: Shearwaters

By Shannon Lyday

Flock of Sooty shearwaters. Credit: Annie Douglas

When you think of taking a wildlife-watching trip in the Gulf of the Farallones National Marine Sanctuary, you might think of braving rough waters to see breaching whales and barking sea lions.  However, the nutrient-rich waters also provide food to numerous seabird species.  Fall is a great time to view these incredible birds, many which are truly pelagic—meaning they only come to land to breed.  In September, you might see several different shearwater species, flying close to the surface of the water, alternating flapping wings with long glides.

Shearwaters are a family of seabirds that are truly amazing to watch glide over the ocean waves.  They are members of the Procellariidae family—the tubenoses—aptly named for their ability to excrete salt through specialized tubes on their bills.  This desalinization system enables them to drink seawater, one of many adaptations to a life at sea. 

They feed mainly on fish and squid, sometimes “swimming” down 40 feet to catch their prey. The most common shearwater species sighted in the Gulf of the Farallones are the Sooty Shearwater, Pink-footed Shearwater, and Buller’s Shearwater. These shearwater species breed on islands in the Southern Hemisphere, migrating north to central California waters in the late summer and fall.

Shearwater Species

In July, hundreds of thousands of Sooty Shearwaters (Puffinus griseus) arrive from their breeding grounds off New Zealand. Their migration routes documented in recent electronic tagging studies have recorded a remarkable transequatorial journey of around 65,000 kilometers (39,000 miles).  Often large flocks of these dark brown shearwaters can be seen right from the coast. 

The Pink-footed Shearwater (Puffinus creatopus) is a large gray-brown shearwater with white underparts.  It nests on islands off of Chile in underground burrows.  It is currently on the Audubon Watch-list due to threats from introduced predators such as rats and cats on breeding sites as well as entanglement in fishing lines at-sea.  Native islanders also harvest about 20% of chicks for food, although this practice is illegal.

One of the most striking shearwaters to see is the Buller’s Shearwater (Puffinus bulleri).  Glimpses of its graceful arcs reveal the boldly patterned upperparts contrasting with a gleaming white body and underwings.  The unmistakable dark M-pattern along with its seemingly effortless long glides can excite even the non-birder.  Buller’s Shearwaters nest in dense colonies on the Poor Knights Islands in New Zealand.

Join us on an upcoming FMSA whale-watching trip to see these extraordinary seabirds who have traveled from down under.

 

Above photo, pink-footed shearwter. Credit: NOAA.  Far right, Buller's shearwater. Credit: Cornelia Oedekoven