By A. Weinstein, Audubon California Seabird Program Manager
It's a Black Oyster Cult and this spring and summer, over fifty Audubon chapter members and leaders have “adopted” one or more black oystercatcher nests on the California coast and are tracking the success of these nests every week through fledging. These committed citizen scientists/conservationists are gathering critical baseline information that will be used to help protect this rare, charismatic species.
In solidarity, and because we love oystercatchers, Marin county resident and Audubon volunteer leader Dr. Linda Trocki and I are tracking the pair of birds nesting at Pt. Bonita cove in Marin county, against the magnificent backdrop of the Golden Gate Bridge. On June 14, the cove was full of hundreds of harbor seals, western grebes and surf scoters. We were thrilled to see three fuzzy chicks watched over by their attentive parents – in fact, we were impressed by the pair’s parenting skills. Over the course of an hour we watched them chase away a western gull, make multiple provisioning trips, and scream alarm calls as a red-tailed hawk flew overhead. And have time left over for a little nap.
On July 10, all three chicks were present and foraging for themselves. If the three fledge in the next week or two, this will be an unusually successful nesting effort, supporting our suspicion that these are exemplary parents!
The data collected by the citizen science participants will be analyzed using methods developed by scientists at the USGS in Oregon, and will tell us how well oystercatchers are succeeding at reproducing here relative to other areas. This information in turn will be used over the coming year as we develop a handbook of oystercatcher and rocky intertidal best management practices to share with agencies, businesses, coastal land owners, and others. The recommendations will focus on reducing disturbance to and degradation of key nesting and feeding areas. Ideal sites for oystercatchers – where they occur in highest densities – are characterized by sea stacks found just offshore with nearby marine terraces and low gradient intertidal areas with rich mussel beds. Simple actions like moving out of the area when birds make alarm calls or appear agitated can mean the difference between nest success and failure for a pair.
In June Audubon California conducted three workshops co-led by the Mendocino Coast , Monterey, and Madrone Audubon chapters, with participation from California State Parks and the Bureau of Land Management’s California Coastal National Monument. The workshops attracted 95 enthusiastic participants who learned about the results from last year’s first-ever statewide oystercatcher survey, https://sites.google.com/site/blackoystercatcherca/home and signed up to track this year’s nests.
“We were surprised and thrilled to find so many oystercatchers and nests in last year’s first-ever breeding season survey,” said Angela Liedenberg, an environmental scientist with State Parks In Mendocino county.” Because of the survey, we know how important the Mendocino coast and State Parks holdings are to the species in the state. We are looking forward to working with Audubon to describe and carry out best practices to conserve oystercatchers.”
“Our chapter loves our oystercatchers,” said Joleen Osello, conservation chair of Mendocino Coast Audubon, “and we were so inspired last year by what we found and the contribution of our work to understanding and conserving the species and the rich and threatened marine intertidal zone. We look forward to much more!”
(Photos by Don Roberson and R. LeValley)