Have you ever sat on the rocks along Monterey Bay and seen a couple of dark bird with a distinctive reddish-orange bill fly by, making a loud whistling sound? To some that is the annoying sound of a black oystercatcher, but to many that is the sound of an oystercatcher putting up a show.
The black oystercatcher is the only shorebird that spends the entire year on the rocky shoreline. It is roughly the size of a crow, but with longer legs and bill. The black oystercatchers range extends from the Aleutian Islands in Alaska to Baja California in Mexico. Their diet consists of invertebrates that live on the intertidal zone, such as limpets, mussels, chiton, and crabs.
Black oystercatchers are very territorial and defend their territory year round from other oystercatchers. Their nest is a shallow depression lined with small pebbles and shells, and can be found above the high water mark on the leeward side of islets, large rocks, and sometimes on the beach. Their incubation period is 26-28 days. It takes another 35-40 days for the young to fledge. Both sexes incubate and provide for the young. Before getting kicked out, fledglings remain with the parents for 2-6 months in order to learn how to forage on their own.
On the Central Coast, volunteers from the Pacific Grove Museum of Natural History and Point Lobos State Natural Reserve monitor black oystercatcher reproductive success for the California Coastal National Monument. This multi-year effort to collect baseline information is needed to better understand oystercatcher productivity and threats to their habitat. This project is a collaborative effort between the Bureau of Land Management (BLM) and Audubon California. Volunteers are a crucial monitoring component and provide an enormous amount of additional information, thanks to frequent site visits and observation reporting. After a month or two, volunteers become “oystercatcher gurus” that not only collect observations, but help educate the community and tourist. Volunteers are very important during the peak of the season and help with locating new oystercatcher pairs, tracking known pairs to see when they lay eggs and when the eggs hatch, monitoring chick growth, and reporting fledgling survival. The amount of time the volunteers dedicate to this project is helping with the accumulation of data that will eventually be analyzed to provide a greater understanding of the species. Currently, the black oystercatcher is considered a Species of Conservation Concern by the U.S. Fish and Wildlife Service and is on the Watch List for the Audubon Society.
Next time you visit our shoreline, look for the black oystercatcher in the intertidal zone, removing limpets or mussels. Better yet, listen for that distinctive sharp whistle that is hard to miss and easy to remember.
- Hugo Ceja is an Independent contractor for Audubon California and a volunteer project Co-coordinator for the CCNM.
More information on the black oystercatcher can be found here.