California’s campaign to curb an invasive swan population appears to be paying off, with new state data showing the number of mute swans in the wild has been cut roughly in half in less than a year.
The drop comes after Gov. Gavin Newsom last year signed legislation permitting landowners and licensed hunters to kill the birds, despite pushback from animal rights advocates. At the time, an estimated 15,000 mute swans were roaming California, with the bulk of them concentrated around the Suisun Marsh near the Bay Area.
The law took effect Jan. 1, and its impact shows up clearly in the California Department of Fish and Wildlife’s latest waterfowl breeding survey, released last week. The annual report, which tracks duck and goose populations statewide, now puts the mute swan count at about 7,400 — a 53% decline from a year earlier.
The turnaround is striking given how fast the species had been multiplying. As recently as 2022, state wildlife officials counted only about 1,500 mute swans in California.
“Let’s hope that things trend in our favor,” said Melanie Weaver, the department’s waterfowl coordinator, referring to continued efforts to manage the population.
Mute swans are known for their striking white plumage and orange-and-black bills, but they are not native to North America — they originated in Europe and Asia. California outlawed keeping them as pets or bringing them into the state without a special permit back in 2008. Even so, escaped or released birds eventually established wild populations here.
Biologists and wetland ecologists say the swans pose a serious risk to the fragile ecosystems of the Sacramento-San Joaquin Delta. The birds can weigh up to 30 pounds, are highly territorial and do not migrate — meaning they stay put and can quickly strip a marsh of the submerged vegetation that native species depend on. During breeding season, mute swans are also known to attack or kill native waterfowl, including ducks and geese.
Still, the birds have their defenders, with some advocates arguing that nonlethal methods could have been used to manage their numbers instead. Despite that opposition, the legislation passed without a single “no” vote in the state Legislature, according to the CalMatters Digital Democracy database.
The law authorizing the culls will remain in place until Jan. 1, 2031.
Original source: CalMatters
