Taking Action to Avoid Extinction: Successful Regional-Scale Lethal Control of Barred Owls Supports a Federal Strategy to Save Spotted Owls

Abstract

Invasive species disrupt biological communities, but lethal control of invaders often meets staunch resistance, posing a conundrum for policymakers. For instance, the human-mediated spread of barred owls from eastern to western North America threatens numerous native species—including the iconic and listed spotted owl—spurring intense debate about whether to lethally control this charismatic but invasive species. A recent US Fish and Wildlife Service strategy, in particular, has drawn strong criticism based on untested claims that barred owl control is unscalable and doomed to failure. Contrary to such claims, we conducted successful lethal controls across >50,000 km2 in California, removing 3373 barred owls—around one third of the state's current population. Critically, monitoring revealed that removals stabilized spotted owl populations and halted the establishment of barred owls. Our work provides direct support for the federal strategy to address this pressing issue and highlights general strategies to maximize conservation while minimizing invader killing.