Highlights
Dogs and sterile "Judas" nutria are joining the war against invasive rodents in the Delta, thanks to over $10 million in new state funding.
A growing menace in the form of 15-pound swamp rodents is threatening Delta waterways, and the state is throwing money, hunting dogs and birth control at the invasive pests which have the potential to destroy crops and wetlands.
The California Department of Fish and Wildlife has received $10 million in new funding for the eradication of nutria, or coypu, which are native to South America and have found their way to the Golden State after wreaking havoc in Louisiana and other places. Louisiana has lost hundreds of thousands of acres of wetlands to the rodent, a voracious herbivore with a largely indiscriminate palate
Gov. Gavin Newsom’s recently-announced budget includes almost $2 million for the CDFW’s nutria program. The Delta Conservancy, a state agency dedicated to preserving the waterway, has awarded it $8.5 million over three years.
Since it began a year ago, the program has confirmed over 600 nutria dead, either trapped and killed by agency employees or reported by citizens, according to department spokesperson Peter Tira.
Until now, the CDFW has had just one full-time employee assigned to the case, while other employees juggle nutria control with other duties. The new money will allow the state agency to hire more staff and try methods inspired by a successful eradication effort in the Chesapeake Bay.
One such project is the use of “Judas nutria,” sterilized swamp rats with radio collars who lead hunters back to their families. Nutria are very social, and often live in big colonies.
The program is also bringing in dogs trained to detect nutria. They will be trained to point, not hunt the giant rodents, which have been known to seriously injure dogs who get too close.
“The more nutria that disperse into the Delta, the more likely they are to find each other and establish a breeding population,” Valerie Cook, who leads CDFW’s nutria program, said in a written statement. “Each of these colonies include several breeding females that are able to produce 3 litters of young every 13 months – the average litter size for adult females in California is nearly seven.”
There are no natural predators or cold snaps to check the population here, as there are in the nutria’s native South America, and they reproduce quickly. Almost every female caught in California so far has been pregnant, Tira said.
The mammals especially like to dig up tender roots, causing plants to die and turning marshes and wetlands into open water. But the most immediate risk posed by a nutria invasion is the way they burrow into dams and flood-control levees, Tira said.
“They burrow underwater, so you can’t always see the damage,” Tira said. “It’s a very real danger. We’ve seen levee collapses in Texas and significant damage in Louisiana.”
Louisiana offers hunters a bounty for nutria, which they just bumped up to $6 per tail. Celebrity chefs and activist organizations have even offered up nutria recipes in an effort to encourage hunting.
California is taking a more surgical approach, with a focus on eradication, rather than managing the population. Instead of offering a bounty, they encourage people to take a photograph and report the sighting to California Fish and Wildlife, either through the agency’s website or by phone at (866) 440-9530.
Still, CDFW has reversed the no hunting stance it took when nutria first appeared in the state in 2017. With a license, it’s now legal to fry up some swamp rat, Cajun style (though, Tira cautioned, they’re easily mistaken for native species, including beavers, river otters, and muskrats).
“They’re a rodent and a non-game animal, so licensed hunters can hunt them at any time and in any numbers,” Tira said. “Landowners can take them at any time, just like any other varmint.”
