From Oregon Marine Reserves Newsletter:
"While the Black Oystercatcher has a conspicuous presence on our coast, little demographic information has been collected on this seabird in recent years. Starting in 2015, Portland Audubon and partners coordinated a statewide survey to obtain an updated population estimate and learn more about their distribution at Oregon’s marine reserve sites and along the Oregon coast. This study relied on community scientists, members of the public that have been instrumental in monitoring these birds in the summertime.
Findings from this study have recently been published in Northwest Naturalist. The study estimates the current population in Oregon to be approximately 500-600 birds, and the breeding population to be small but stable. In addition, the study found Black Oystercatchers are most prevalent on the south coast."