On California Coast, Endangered Tern Depends on Healthy Anchovy Population

Early on Monday mornings from May through August, Kate Grabenstein heads to Huntington State Beach, south of Los Angeles in Orange County, to keep an eye on endangered California least terns as they nest in the sand and raise their young. “I love listening to them call when they return in the spring,” says Grabenstein, a volunteer with Sea & Sage Audubon Society’s least tern project. “It gladdens my heart.”

Grabenstein is concerned about the least tern’s survival because these little birds depend on northern anchovy and other forage fish to feed their young—and anchovy availability along the West Coast varies significantly depending on water temperature and other conditions. This can devastate terns and other predators because federal fishery managers don’t adjust commercial catch limits to account for the needs of wildlife, even in years when anchovy are scarce.

Anchovy are vital prey for more than 50 species, including seabirds, salmon, tuna, whales, sea lions, and other marine mammals, and are an essential part of one of the most vibrant marine ecosystems in the world. That’s why The Pew Charitable Trusts has long advocated for better anchovy management—including setting catch limits based upon up-to-date population estimates. 

Growing up in rural Nebraska, Grabenstein was captivated by western meadowlarks around her childhood home as well as the dippers she saw at summer music camp in the Colorado Rockies. “I was outdoors a lot as a kid,” she says. “I always had my eye on what was happening.”

Grabenstein moved to California in 1984 to attend graduate school and today teaches piano. As a volunteer docent at Huntington Beach, she keeps people, predators, and pets from disturbing these endangered shorebirds and provides information to visitors. Pew caught up with her to learn more about the terns, and about how improving anchovy protection can benefit the birds.

Q: What draws you to least terns?

A: I am so inspired by these small birds and the journey they make from South or Central America—scientists aren’t sure—to breed in Southern California. And they are extremely industrious. They deliver fish to their young and they are off again, looking for more fish.

Q: How did you become involved with the least tern project?

A: My daughter was fascinated with birds and wanted to volunteer when Sea & Sage Audubon and California State Parks started the monitoring program at Huntington State Beach. She was a minor, so I had to go down there with her. After she graduated from high school, they asked me to stay on, and I did.

Q: How do people react when you ask them to give the least terns some space?

A: They’re mostly supportive. Children are eager to view the chicks when I have my spotting scope with me and seem genuinely concerned with their survival.  Adults who have visited the informational kiosks want to know how the least terns are faring each season.

Q: Has the California least tern population grown since it was added to the endangered species list in the early 1970s?

A: The number of breeding pairs has increased, but the number of least terns that fledge each year varies a lot. Some factors are predation and the availability of food. Two or three years ago, only larger fish were available, and the chicks couldn’t eat them. Anchovy are ideal for least terns to feed to their young, because these fish are small. Which is why it’s so important to make sure there are enough anchovy available for these small shorebirds and other wildlife.

Q: What can federal fishery managers do to help least terns and other forage-fish-dependent wildlife?

A: Replace archaic anchovy regulations with commercial fishing limits that reflect up-to-date population data. National Oceanic and Atmospheric Administration Fisheries hasn’t officially counted northern anchovy off the coast of California since the 1990s. The agency also hasn’t changed the amount fishermen can take—no matter how depleted the population becomes. Meanwhile, seals, brown pelicans, and other species have had die-offs in recent years, which biologists suspect is due to an insufficient supply of forage fish.

Paul Shively directs The Pew Charitable Trusts’ work on ocean conservation in the Pacific.