A pair of Black Oystercatchers (Haematopus bachmani) established a nest in June 2022 at “Tern Town”, an island located in Hayward, California along the eastern side of the San Francisco Bay. This is the first documented occurrence of oystercatchers successfully nesting and fledgling young in association with California Least Terns. The island provides nesting habitat for three special status species. Since 2015, and for a total of six breeding seasons, the endangered California Least Tern (Sternula antillarum browni), the threatened Western Snowy Plover (Charadrius alexandrinus nivosus) and species-of-special-concern Black Skimmer (Rynchops niger), have nested successfully, in association with American Avocet (Recurvirostra americana) and Black-necked Stilt (Himantopus mexicanus). We collected shells near the oystercatcher nest to assess their diet. Diet data showed the oystercatchers foraged on, in decreasing order of abundance, Japanese Little-necked Clams (Ruditapes philippinarum), Ribbed Mussels (Geukensia demissa), Bent-nose Clams (Macoma nasuta), Limpets (Patellogastropoda sp.) and Bay Mussels (Mytilus edulis). This new report on breeding Black Oystercatchers indicates that managing habitat for California Least Tern, Western Snowy Plover, and Black Skimmer can also benefit Black Oystercatcher. This site-specific information on breeding Black Oystercatchers supports recovery plan tasks that are consistent with managing habitat for California Least Tern, Western Snowy Plover and Black Skimmer.

David (AKA “DOC QUACK”) Riensche, a Certified Wildlife Biologist, is a Wildlife Biologist II for the East Bay Regional Park District where he has worked for over 35 years. For 26 years he has been a member of the Biology Department faculty at Las Positas College, where he teaches courses in biology, ecology, and vertebrate natural history. He is a recipient of The National Association for Interpretation (Region 9) – Outstanding Field Naturalist Award. David holds advanced degrees in both Natural Resource Management and Environmental Education, and an undergraduate degree in Biology (Wildlife). His current wildlife research and habitat restoration efforts are diverse, focusing on the following species and groups: California Least Tern, Western Snowy Plover, Black Skimmer, Forster’s Tern, Western and Clark’s Grebes, Bald Eagle, Ridgway’s Rail, California Black Rail, Burrowing Owl, California Red-legged Frog, California Tiger Salamander, Western Pond Turtle, Salt Marsh Harvest Mouse, San Francisco Dusky-footed Woodrat, Bats, Fairly Shrimp, Central California grassland lizards and small mammals, riparian and oak woodland breeding bird community structure, shorebird nesting population studies, upland gamebirds and waterfowl management.