Half Moon Bay, California: Seabirding on the Continental Shelf

by Debi Love Shearwater, Shearwater Journeys, Inc.

Pelagic Birders on a Shearwater Journeys trip at Half Moon Bay © Debi Shearwater

Pelagic Birders on a Shearwater Journeys trip at Half Moon Bay © Debi Shearwater

Half Moon Bay is part of the Monterey Bay National Marine Sanctuary, the largest protected area in the United States and one of the most productive areas for pelagic seabirding in the world.  Pelagic birding boats cruise out to the continental shelf, where the ocean floor drops off and creates a massive upwelling of food. This micro-marine smorgasbord attracts a plethora of seabirds—including albatrosses, shearwaters, storm-petrels, jaegers, terns and alcids—and it offers a great day of birdwatching.


Late July through mid-October is the best time to do a trip from Half Moon Bay. September is the very best month to see the largest variety of seabirds and marine mammals. Late July and early August has been a good time for the rare Hawaiian Petrel. Unlike Monterey Bay, there is no shelter from the prevailing northwesterly winds so it generally not seafaring weather in winter and spring.


Rhinoceros Auklet, Half Moon Bay ©  Beth Hamel:Shearwater Journeys

Rhinoceros Auklet, Half Moon Bay ©  Beth Hamel:Shearwater Journeys

Half Moon Bay offers essentially the same suite of seabirds as Monterey Bay with one outstanding exception—the Marbled Murrelet. Because of the proximity of Half Moon Bay to the Farallones Islands, Tufted Puffin is also more often observed on these trips.

Tufted Puffin, Farallon National Wildlife Refuge © Debi Shearwater

Tufted Puffin © Debi Shearwater

Like Monterey, several species of rare seabirds have been discovered here, including Laysan, Short-tailed and Salvin’s Albatrosses, and White-chinned and Great-winged Petrels. Mixed-species flocks of storm-petrels are also observed on Half Moon Bay.


Killer Whale © Debi Shearwater

Killer Whale © Debi Shearwater

Marine mammals are an added delight on Half Moon Bay pelagics. The bay has essentially the same marine mammal species as Monterey with a few exceptions. Sea Otters, for example, are rarely found here, while Harbor Porpoise and Bottlenose Dolphin are more easily observed at Half Moon Bay. Steller’s Sea Lions routinely hang around the many buoys. All of the whales and other cetaceans found at Monterey Bay can be found at Half Moon Bay. Once, we witnessed a young Killer Whale learning how to perfect his killing technique on Common Murres. Humpback Whales, in particular, can be very abundant here.


Most pelagic trips for birders operate on fixed schedules that require advance booking. The operator will typically send an information sheet as to how to dress and what to bring. In a normal season, temperatures can be quite cool offshore. A warm jacket and lunch are essential. It is always best to study the seabirds and marine mammals prior to the trip. Check the operator’s website for past trip reports to get an idea of species recorded.

It is always best to join a dedicated pelagic trip provided by a birding company. And look for a good ratio of leaders to guests, because that provides the highest quality experience. Half Moon Bay is easily reached from the San Francisco Bay Area. Advanced bookings are also necessary for motel rooms, which are in short supply. By the way, no commercial whale watching trips are offered from this port so if you want to see mammals, you’ll have to book a pelagic birding trip.


About the author:

Debi Shearwater, owner of Shearwater Journeys, Inc., has operated west coast pelagic trips for more than forty years and is a leading expert in global seabirding.

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