Protecting Birds in a Changing Ocean: How Marine IBAs Can Guide Ocean Planning

Every year, birds travel extraordinary distances to reach the productive coastal waters of California, where they depend on critical marine and coastal habitats recognized as Important Bird Areas (IBAs). Sooty Shearwaters undertake one of Earth’s longest migrations, breeding in New Zealand before crossing the vast Pacific Ocean to feed in places like Monterey Bay, where they forage offshore within the Piedras Blancas Marine IBA near Cambria. Elegant Terns travel as far south as Chile, but some first feast in places like Aramburu Island in Richardson Bay, part of Audubon’s sanctuary, and nest and forage within the Palos Verdes Marine IBA, an area that supports an estimated two percent of the global population. IBAs are much more than lines on a map—they reflect incredible bird journeys and help us protect the places birds like Sooty Shearwaters and Elegant Terns depend on throughout their remarkable migration cycle.

What are Important Bird Areas (IBAs)?

Important Bird Areas are sites identified using a global standardized, science-based criteria that recognize places essential for breeding, migrating, and wintering birds. The global IBA program was established by BirdLife International in 1979 and managed by the National Audubon Society in the U.S. since the early 1990s. Now 14,000 IBAs have been recognized across 200 countries, and Audubon has helped establish 2,800 within the U.S (read more about IBAs here)

These IBAs identify habitats that support significant populations of birds, whether breeding colonies, migratory stopover sites, or rich feeding areas in the ocean. Used by Audubon conservation teams, scientists, policy experts, and chapters as well as federal agencies and NGOs, IBAs are a powerful tool to guide conservation priorities on a local to hemispheric scale. These significant areas are referenced in everything from Marine Protected Areas (MPAs) and fishery regulations to national monument designations.

Why California’s Marine IBAs Matter

California’s coastal and offshore waters form one of the world’s richest marine ecosystems, shaped by ocean conditions that create productive habitats. Monterey Bay, for example, has a deep submarine canyon and seasonal upwelling that, combined with the southward flowing California Current, brings cold nutrient-rich waters to the surface. This results in plankton blooms that support spectacular schools of fish and other marine life, attracting species like the Ashy Storm-Petrel, Black-footed Albatross, Laysan Albatross, and Pink-footed Shearwater that gather offshore to feed.

The 18 Marine IBAs in California, including the Monterey Bay and San Mateo Coast IBA, recognize and spotlight these “habitat hotspots” that support high concentrations of seabirds and other marine wildlife. As an easy-to-understand, science-backed framework, the IBAs help decision-makers and partners consider the impacts of activities offshore.

Updating Marine IBAs and the Future of Offshore Wind

As California transitions to clean energy, offshore wind energy has emerged as an important renewable energy source with the potential to generate large amounts of electricity. In fact, the potential capacity for offshore wind generation represents more than triple the combined generating capacity of all U.S power plants currently in operation (read more here). Audubon is working with agencies and developers to advocate for policies that prioritize wildlife protection and ensure offshore wind is deployed responsibly (read more about birds and offshore wind here). 

In California, the Bureau of Ocean Energy Management (BOEM) has designated two Wind Energy Areas off the north coast in Humboldt and off the central coast in Morro Bay. Marine IBAs are more relevant than ever to help Audubon evaluate how offshore wind energy development may affect critical bird habitats and advocate for policies that ensure clean energy is developed in ways that avoid and reduce impacts on seabirds and the marine ecosystems they rely on.

To support responsible offshore wind siting, we updated California IBA maps to understand how seabirds are currently using California’s marine environment. The original maps included overlapping boundaries that were difficult to interpret and species population estimates that likely underestimated seabird use in these large offshore regions. Since the original IBA estimates were quantified, NOAA has developed models that we used to calculate more accurate estimates of populations within the marine IBAs. We refined IBA boundaries and updated species population estimates using long- term predicted seabird density models developed by NOAA and partners from 21 survey datasets, including aerial and ship-based at-sea bird counts, that were collected between 1980 and 2017 (access NOAA report here).

The updated IBAs provide a more accurate picture of seabird use across California’s IBAs. When evaluating potential impacts of the Morro Bay Wind Energy Area, we now see that the Even Keel Wind lease area overlaps with Piedras Blancas IBA, which supports an estimated population of 10,550 Sooty Shearwaters. Understanding this overlap allows us to identify strategies to minimize potential impacts to this species. For example, we can research when and at what height Sooty Shearwaters are flying throughout the year, as well as evaluate whether turbine lights could help them detect and avoid these structures. These insights can inform how the lease area is designed and operated to reduce risk to birds. Updated estimates like these provide a quantitative, science-backed foundation to support advocacy and guide responsible offshore wind energy development.

How Will You Use IBAs?

Marine IBAs are a powerful tool for understanding and protecting the places birds depend on most. We invite you to explore the IBA Hub to discover Important Bird Areas near you and learn how these regions support seabirds and their habitats.

By sharing this information with your communities, local partners, and decision-makers, you can help ensure that IBAs inform conservation efforts and guide responsible ocean planning. Together, we can advocate for policies that protect birds and the habitats they rely on now and into the future!

For more information about California’s Marine IBAs or questions about how to use them in your work, please contact Keilani Bonis-Ericksen at k.bonisericksen@audubon.org.