Seas & Shores

Seabird “Preyscapes” in the Age of Climate Change

How breeding seabirds respond to climate-driven changes in their food sources

Last week saw the publication of a landmark study co-authored by Audubon scientists, which tells the story of how breeding seabirds in the Gulf of Maine respond to climate-driven changes in their food sources. The report’s findings are full of insights for protecting the Pacific Flyway seabird cousins of these eastern seaboard species.

The study, which appears in Marine Ecology Progress Series, analyzes reproductive success of Atlantic Puffins, Razorbills and Common Murres (also a west coast species) when preferred, high-energy prey are less available due to warming waters. Significant changes in chick diet were seen across the study period for all three species, coinciding with major temperature increases. The authors found that razorbills and murres need a more consistent diet of high-quality forage fish than puffins, which more frequently exploited lower-quality but more readily available food during food shortages.

On the west coast, prey studies at seabird colonies such as the Farallon Islands have similarly shed light on the importance of high-energy prey such as herring and anchovy, as well as how seabirds cope in the absence of these prey. Some seabirds skip breeding for a year or more; others attempt breeding and abandon their nests when prey disappears; and still others switch to lower-quality prey and can salvage their breeding season.

The Audubon network on the west coast has for almost 10 years relied on these studies to advocate for protection of the “preyscape” for California least terns, brown pelicans, sooty shearwaters, black-footed albatross, and many other coastal and pelagic birds.

The publication of the new Audubon study underscores why our society must support long-term studies that provide an unbroken time series of information on how seabirds respond to changes in ocean conditions that affect their prey. This information is what allows to understand the strategies of seabirds in a changing world, which in turn is essential to inform conservation actions to help them adapt. Yet, often these studies are threatened or scrapped from lack of funding, hurting conservation.

The new study also provides support for the need to protect and restore forage fish populations along our coasts as climate change increases global ocean temperatures. “Just like birds on land indicate the health of terrestrial ecosystems, seabirds too can tell us about the state of the ocean which supports both coastal communities and countless wildlife. What they’re saying is very clear: we need to protect and enhance coastal populations of forage fish,” says said Dr. Steve Kress, executive director of Audubon’s Seabird Restoration Program and co-author of the study.

You can help today with protecting forage fish for our seabirds on the west coast and in the rest of the country. Please contact your member of Congress and urge their support for the Forage Fish Conservation Act (HR2236), which will expand protections for forage fish in the country’s only fisheries management law, the Magnuson-Stevenson Act. At the moment, the law does not differentiate between forage fish and larger fish, faulting to manage forage fish for their critical role in the ecosystem, as they transfer energy from tiny organisms like zooplankton to larger predators including seabirds, marine mammals, and larger fish.  By updating and improving the Magnuson-Stevenson Act via HR 2236, the foundational fishes of our marine ecosystems can begin to recover and continue supporting the wildlife, people and economies that depend on them.

How you can help, right now