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New data from our Santa Ana River Mouth Monitoring Project (SARMMP) reveals a significant amount of illegal off-leash dog activity in the area, which threatens the habitat of endangered shorebirds such as the California Least Tern and Western Snowy Plover.

The Santa Ana River mouth is a 13.2-acre parcel of land owned by four governmental agencies: the California State Lands Commission, California State Parks, the County of Orange, and the City of Newport Beach. The fragmented ownership of the area causes land management issues and a lack of consistent law enforcement on illegal beach activities, such as the presence of off-leash dogs. By providing detailed reporting data to these agencies, we hope this critically important coastal area can be managed more effectively in the coming years.

Why It Matters

This contested coastal area drains one of Southern California’s largest watersheds, the Santa Ana River watershed. It serves as a critical habitat for two endangered shorebirds: the California Least Tern and the Western Snowy Plover. Both birds inhabit the Santa Ana River Mouth to raise their young alongside one another. For more information about these shorebirds, check out this Coastkeeper blog post.

These species have inhabited the Santa Ana River mouth for thousands of years. Now, harmful human activity near the mouth threatens their safety. One of the biggest issues facing these birds is the domesticated off-leash dogs that often accompany visitors.

The presence of off-leash dogs threatens the birds’ ability to nest and feed in the river mouth. Both species have evolved to respond to threats, whether it be rising seas or predators, by fleeing and abandoning their nests and chicks. Regardless of land management lines, dogs are not allowed to be off-leash anywhere along the Orange County coast.

This combination of inconsistent land management, endangered bird habitats, and misinformed beachgoers led us to start SARMMP in 2019.

The 2022 Report

Throughout 2022, a dedicated team of 36 volunteers conducted 1,275 surveys of the river mouth. These volunteers were provided comprehensive hands-on training by our staff, ensuring accurate data collection and analysis.

The results of the surveys revealed a concerning trend related to dog activity. We found that when dogs were present at the beach, they were off-leash 71% of the time. This dog activity contributed to the over 9,000 bird disturbances witnessed during our surveys. Both on and off-leash dogs were observed primarily in the southern half of the Santa Ana River Mouth, where the California State Lands Commission and the City of Newport Beach hold ownership.

Read the full report here.

The Future of the Santa Ana River Mouth

We delivered our 2022 SARMMP report to all four land-holding agencies in the spring of 2023. Our 2021 annual report was used by the California State Lands Commission to revise the lease term for Orange County Flood Control operations in the area and encourage additional law enforcement in the area. We anticipate our 2022 annual report will also be used by state and local agencies to make management decisions for the river mouth.

We will continue to monitor the river mouth through 2025 thanks to additional funding from the California Coastal Conservancy. We will also increase our public outreach and education efforts to inform beachgoers about the endangered bird species that call the river mouth home.

Interested in helping our research? Reach out to Ray Hiemstra at to volunteer for our Santa Ana River Mouth Monitoring Project.