The Trump administration’s budget slashers have taken aim at programs designed to protect the northern spotted owl, an endangered species whose habitat extends from the upper Pacific coast down to Marin, the southern edge of its territory. Last year, the Biden administration approved a plan that sought to bolster spotted owl populations by killing as many as 450,000 barred owls in California, Oregon and Washington over three decades. Biologists at the Point Reyes National Seashore and Point Blue support the removal of barred owls, a larger, more aggressive bird native to eastern states that has made its way west. Barred owls can quickly outnumber spotted owls because they need less territory, have a more diverse diet and enjoy greater reproductive success. In West Marin, although the population of barred owls is small, wildlife managers would like to keep it that way. But in May, the Trump administration canceled three grants that would have funded barred owl removal projects. One of those, conducted by the University of Wisconsin, would have culled the owls in parts of Mendocino and Sonoma Counties. “Marin is still in the early stages of invasion by barred owls, with just a few individuals detected each year,” said Renée Cormier, a senior avian ecologist at Point Blue. “If they were to become established in greater numbers, we would expect to see the decline of northern spotted owls here, as has been the case throughout their range. A reduction in management in areas immediately to the north certainly could increase the rate at which we have individual barred owls moving into Marin.” Of the eight barred owls spotted in Marin this year, six were culled, Ms. Cormier said. The federal cuts will not impact monitoring in the seashore, according to Earl Perez-Foust, a park spokesman. “There have been no funding changes to the barred owl management program at Point Reyes National Seashore, and all work is planned to continue as needed and is consistent with previous efforts,” he said. Dave Press, a park service biologist, has said previously that seven barred owls were documented on land managed by the seashore between 2018 and 2023. Six of them were lethally shot and the only one found in 2023 left the area before it could be culled. Point Blue and the park service monitor roughly 100 nesting sites inhabited by northern spotted owls. For the last several years, nearly all those sites have been occupied, a sign that their population is holding steady, Ms. Cormier said.