Saturday, November 1, 2014

Pink-footed Shearwater offshore San Diego

Pink-footed Shearwater
Pink-footed Shearwater. Off San Diego, California. October 4, 2014. Greg Gillson.
The Pink-footed Shearwater has a very similar plumage to Black-vented Shearwater, which I discussed earlier. Grayish-brown above and generally white below, this bird has a grayish hood, dark vent, and extensive dark markings under the wings, including all the flight feathers.

Unlike all other West Coast shearwaters (except the closely-related, but all-dark, Flesh-footed Shearwater) Pink-foots are larger and fly higher off the water with deep, slow wing beats and extensive gliding. The thick bill is pink with a dark tip. The pink legs and feet are not unique to this one species of shearwater.

They breed December-February in the southern Hemisphere and migrate north as far as southern Alaska from April-October. On West Coast pelagic trips they can be found singly or up to a few thousand in flocks mixed especially with Sooty Shearwaters, often around commercial fishing vessels pulling in their nets of fish or shrimp. They are infrequently seen from shore, but occur regularly from 3-30 miles offshore. I counted 6 individuals on the October 4th pelagic trip from San Diego, and got these two photos. Of course, you're often not certain whether you are seeing the same individual over and over again or different ones when at sea over the period of several hours and quite a bit of traveling.

These birds breed on only 3 islands off South America owned by Chile. Thus, while they are fairly numerous (perhaps 100,000 individuals), their population is at risk due to common island threats to burrow nesting birds such as habitat destruction due to feral pigs, goats, or rabbits or even invasive plants. Rats invade nest burrows and eat eggs and kill young chicks. Ocean conditions affecting food (El Niño, or climate change), over-fishing, by-catch in fishing nets, oil spills, plastic ingestion, and other similar threats can cause sudden drops in population to all ground-nesting seabirds scattered about the world's oceans.


Pink-footed Shearwater