State pledges millions to battle huge, destructive swamp rodents
Nutria destroy plants and burrow into dams and flood-control levees
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. In Louisiana, hundreds of thousands of acres of wetlands have been damaged by the rodent, a voracious herbivore with a largely indiscriminate palate.
Gov. Gavin Newsom’s recently announced budget includes almost $2 million for Fish and Wildlife’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 spokesman Peter Tira.
Until now, Fish and Wildlife has had just one full-time employee assigned to the effort, 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 Maryland’s Chesapeake Bay.
One such project is the use of “Judas nutria,” sterilized animals 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 at,
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 Fish and Wildlife’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 range, and they reproduce quickly. Almost every female caught in California 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 the state 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, the state encourages people to take a photograph and report the sighting to Fish and Wildlife at wildlife.ca.gov or 866-440-9530.
Still, the agency 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 nongame 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.”