On Wednesday, a three-judge panel from the Ninth Circuit rejected environmentalists’ appeal to overturn a U.S. Fish and Wildlife Service (USFWS) policy that allows the taking of one owl species to help recover another. Friends of Animals initially sued the USFWS over a 2014 plan to kill thousands of barred owls (on the left in the image above), which have begun to encroach on the forest habitat of threatened spotted owls (on the right). The spotted owls are listed as threatened under the Endangered Species Act, while the barred owls are only protected under the Migratory Bird Treaty Act. USFWS argued killing the barred owls is an experiment to determine whether reducing barred owls numbers would ultimately benefit spotted owls.

More specifically, at issue in the case, was both the threatened northern spotted owl and the barred owl. The northern spotted owl resides in southwest Oregon and northwest California. Meanwhile, the barred owl originally hails from the eastern U.S. but because it is adaptable it has begun to invade the northern spotted owl’s habitat. The barred owls are aggressive and outcompete the spotted owls for food, as well as physically attack them.

Due to this issue, USFWS drafted a recovery plan in 2008, which concluded that the barred owl constitutes a greater threat to the spotted owl than was envisioned when the spotted owl was originally listed in 1990. In response, experiments involving the two were called for as part of the plan and the Department of Interior then issued take permits for up to 1,600 barred owls over four years in a small part of their habitat range. Friends of Animals and Predator Defense then challenge this policy, arguing that the Interior cannot allow the harming or take of one species to study another.

The complaint was initially dismissed in 2015, when a U.S. District Court judge found that the USFWS experiment was legally allowed under the Migratory Bird At. The judge noted that a specific provision of the Act allows for the killing of protected birds for scientific use, propagation, or museum use. Friends of Animals then appealed to the Ninth Circuit Court of Appeals in October, arguing that the Migratory Bird Treaty Act exception cited by the District Court judge must benefit the bird the service is considering killing.

The Ninth Circuit panel unanimously disagreed with Friends of Animals and found that the law imposes few substantive conditions and gives the Interior secretary wide discretion.