Audublog

Black Oystercatcher in California

May 5th, 2011 · by Anna Weinstein

This large, handsome shorebird is often seen on our coast, calling in loud springtime territorial displays, hunkered together in small winter flocks and prying limpets off rocks. Yet the species is rare across its range and poorly understood in California in particular. We’re taking steps to improve our understanding of this unique marine bird and help safeguard its future. You can help, too.

(photo by Ron LeValley)


Black Oystercatcher (Haematopus bachmani) is an a two-species genus withAmerican Oystercatcher, found in Baja California and points east. It is one of five “rocky intertidal obligate” shorebirds on the west coast, and of this guild, the only one that does not undertake large scale seasonal migration – many individuals likely stay in the same place year-round. (The other species in this guild are Wandering Tattler, Rock Sandpiper, Surfbird, and Black Turnstone.) It is also the rarest: the global population is estimated at 10,000-12,000 individuals, with perhaps 10% of that total in California. Oystercatchers favor sheltered areas of high tidal variation supporting plentiful invertebrates such as limpets, snails and mussels , making them sensitive indicators of intertidal habitat quality.

We were inspired to take action in response to a dearth of baseline information on the species in California, enthusiasm on the part of a number of coastal chapters, and the opportunity for us to take the lead in organizing research and conservation here.  We have great starting points in the 2007 Conservation Action Plan developed by federal agency scientists after Black Oystercatcher was designated a Focal Species by US Fish and Wildlife Service, and, the lessons learned and protocols developed by agency scientists and citizen volunteers tracking the species in Oregon over the last five years.

We had decided to kick off our involvement by conducting a pilot breeding season survey at just a few sites in 2011, to better understand what it would require to elevate the effort to larger scales. The subsequent response we received from chapters, independent birders, and agencies was substantial enough to expand the scope of this year’s effort to representative sites across the entire state. A number of Audubon chapters including Redwood Region, Mendocino Coast, Madrone, and Monterey are participating at a very significant level, as are US Fish and Wildlife Service, State Parks,  National Park Service and Bureau of Land Management California Coastal National Monument.

The goals of this year’s survey are to gain an understanding of densities at suitable habitats in the breeding season; establish a baseline to understand trends in use of these habitats over time; generate a new population estimate for the state; use lessons learned from this first year to inform future activities; and, build a network of citizen and professional biologists who are tracking the species and communicating about it. Tools including E-bird, Christmas Bird Count, Google Earth and Google Sites are already playing a key role.

Ultimately, we seek to answer questions related to securing the future of the species: how many Oystercatchers are in California, how are they distributed, and why? Are their population numbers and reproductive success increasing, decreasing, or stable? What are the primary threats to their population, and how important are these threats? What actions, such as the Marine Life Protection Act, are needed to safeguard their future?

You can help Oystercatchers thrive in California. When you are at rocky intertidal shorelines in the spring and summer-  on both islands and mainland areas – take care to avoid their nests,  located just above high tide line. Parent Oystercatchers, which may abandon a nest once it has been disturbed, will let you know you are getting too close by flying overhead and calling loudly. When you see Oystercatchers, put your observations in E-Bird. Finally, just enjoy the sight and sound of these quintessential rocky intertidal birds.

We will report on 2011 survey results this summer. For more information, please visit: https://sites.google.com/site/blackoystercatcherca/home

Categories: Audubon California · Audubon Watchlist · Conservation research · seabirds · Uncategorized

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