Controversial swan hunt appears to work: California’s mute swan population drops

California’s once exponentially growing population of invasive mute swans has fallen by half, less than a year after a new law took effect allowing hunters and landowners to kill them. 

Over the objections of animal welfare groups, Gov. Gavin Newsom last year signed legislation allowing property owners and those with hunting licenses to shoot the nonnative, destructive swans. The mute swan population had ballooned to about 15,000, most around the Suisun Marsh on the outskirts of the Bay Area.

The law, which took effect Jan. 1, appears to be working as intended.

The California Department of Fish and Wildlife last week released its annual waterfowl breeding population survey, a snapshot of duck and goose numbers across the state.

This year, biologists estimated California has around 7,400 mute swans, a 53% decrease from the previous year.

It’s a remarkable decline considering how quickly California’s mute swan population skyrocketed in just a few years. In 2022, state waterfowl biologists estimated there were just 1,500 of them.

“Let’s hope that things trend in our favor,” said Melanie Weaver, the department’s waterfowl coordinator.

The regal white birds with orange and black bills might be lovely, but they’re native to Europe and Asia. In 2008, California banned anyone without a special permit from keeping mute swans as pets or from importing them into the state. Nonetheless, some were brought here and escaped or were released from captivity.

Wetland ecologists and waterfowl biologists say they represent a profound threat to the struggling wetlands of the Sacramento-San Joaquin Delta.  

Weighing up to 30 pounds and fiercely territorial, the swans don’t migrate. As their numbers grow, they can quickly eat through a marsh’s submerged native vegetation on which other species rely. Mute swans also harass or kill native waterbirds including ducks and geese during the breeding season. 

Even so, mute swans have devoted fans who believe there are other ways to control their numbers without killing the beautiful animals. Despite the opposition, no lawmaker voted against last year’s bill, according to the CalMatters Digital Democracy database. 

The law remains in effect until Jan. 1, 2031.