Black Oystercatcher

Peter LaTourrette

The Black Oystercatcher is the charismatic, signature bird of rocky intertidal, one of California’s and the west coast’s iconic habitats. Commonly seen yet globally rare, there is no mistaking its bright orange beak or distinctive call. There are thought to be no more than 12,000 of these birds ranging from the Aleutian Islands through Baja. The species is utterly dependent on rocky intertidal habitats, plying limpets, snails, mussels and other invertebrates from marine terraces and rocky shorelines.

Despite the popularity of Oystercatchers, until recently little was known of its demography (status and distribution) in California. It is a Special Status Species of the U.S. Fish and Wildlife Service due to its rarity and vulnerability to a number of threats. The rangewide conservation action plan developed by the US Fish and Wildlife Service and partners calls for more baseline understanding of the species in California.

In response to this need, and to capitalize on the robust citizen science capacity in our coastal chapters, in 2011 Audubon California conducted the first-ever survey of Black Oystercatcher in California. Over 150 dedicated participants drawn from coastal chapters and from agencies found more Oystercatchers in just a part of our state’s suitable habitat, than were previously estimated for the state as a whole. Over 1300 birds and over 170 nests were detected. We conservatively estimate an overall state population of at least 4000 individuals on the coast and in the Channel Islands, with the previous estimate at just 888 individuals. This combined with high densities of breeding Oystercatchers in certain areas has shone light on the importance of California to the species.

In 2012 an additional >60 surveyors are tracking Oystercatcher reproductive success at 81 nests from Mendocino to Morro Bay. This information will create a more complete baseline assessment, and help to understand the conservation status and trajectory of the species here. There may be more Oystercatchers here than had been thought, but the threats are real and growing: sea level rise, ocean acidification, and increased recreational and commercial use of coastal areas. Audubon will use the science generated by survey participants to create informed list of conservation best practices to disseminate to a broad audience of coastal managers and users.

You can help Oystercatchers by watching and listening for their alarm calls in the spring and summer, when they nest on rocks, islets, and sometimes mainland areas. Leave the immediate area where they are likely defending their nest and brood. Tell others about oystercatchers and how to protect them. And just enjoy this handsome, territorial marine shorebird!