A federal plan to kill barred owls to protect spotted owls interferes with the “evolutionary paths” of the species contrary to environmental laws, according to animal rights advocates.

The Animal Wellness Action and Center for a Humane Economy nonprofits have filed a lawsuit against the U.S. Fish and Wildlife Service to invalidate the strategy.

According to the complaint, the agency approved the plan to shoot barred owls in violation of the Migratory Bird Treaty Act and the National Environmental Policy Act.

“The Service’s plan, if fully implemented, will leave us looking back in thirty years at a half a million carcasses of dead barred owls and no living spotted owls to be found in the forests of the Northwest,” the lawsuit said.

A spokesperson for the Fish and Wildlife Service did not respond to requests for comment, but federal agencies generally do not discuss pending litigation.

For more than three decades, federal protections for threatened spotted owls have resulted in logging curtailments on public lands, but the species has continued to struggle due to the incursion of barred owls onto its habitat.

About 15 years ago, the Fish and Wildlife Service began experimenting with removing barred owls from several areas along the West Coast, culminating in the recent plan to kill more than 450,000 of the birds over 30 years.

The environmental plaintiffs argue the strategy is based on barred owls being an “invasive species” despite evidence they’re native to North America and have naturally been expanding their territory westward through Canadian coniferous forests since the 1800s.

Meanwhile, the Fish and Wildlife Service’s plan is unlikely to be successful because it ignores the “primary reason” for the spotted owl’s dwindling numbers, which is habitat loss due to old growth logging, according to the complaint.

“While this loss of habitat continues at an increasing rate, the Service hides its head in the sand and endeavors instead to reduce the population of a well-adapted and ecologically suitable migratory raptor by means of a thirty-year cull,” the lawsuit said.

The lawsuit argues that shooting the barred owls at night when they’re active, as planned by the agency, will make it difficult to distinguish them from spotted owls.

The agency lacks adequate support for its claim that only a single spotted owl is likely to be accidentally killed per decade under the strategy, especially since training and testing protocols are vague, according to the complaint.

“Even a single poorly trained ‘removal specialist’ could remove multiple spotted owls in a single removal season,” the plaintiffs claim.

The government has improperly discounted the likelihood that hybrids of spotted owls and barred owls will be unwittingly removed or that noise from gunshots will disturb threatened marbled murrelets and other species, according to the complaint.

The plaintiffs allege the strategy isn’t sufficiently site-specific, fails to take a “hard look” at adverse impacts and doesn’t adequately study alternatives to killing barred owls, contrary to the requirements of NEPA.

The lawsuit claims the plan also violates the Migratory Bird Treaty Act because it fails to meet the criteria for killing birds under the law. The plaintiffs have asked a federal judge to overturn the plan’s approval and send it back to the government for reconsideration.

Though the recent lawsuit is the first to challenge the barred owl strategy, several previous federal complaints failed to stop the agency’s removal experiments.

An early legal action in California was dismissed for lack of standing in 2014 and the 9th U.S. Circuit of Appeals rejected arguments based on the Migratory Bird Treaty Act in 2018 and the Endangered Species Act and NEPA in 2022.

“We hold that this experiment will produce a ‘net conservation benefit’ under the plain language of the ESA’s implementing regulations because it allows the agency to obtain critical information to craft a policy to protect threatened or endangered species,” according to the 9th Circuit’s most recent decision.