The flammulated owl is a small insectivorous owl that occupies forests in western North America during the spring and summer breeding season. The species has not been extensively studied across its range but is considered sensitive or at risk by many states, provinces, and forest management agencies. We implemented the largest survey ever performed for this species across multiple western states to assess its distribution and habitat associations. We completed one to three survey visits at 3137 points from 2009 – 2021 and detected flammulated owls at 309 (9.8%) survey points. We used machine-learning occurrence modeling to estimate habitat associations. We found flammulated owl presence to be most strongly associated with a specific climate envelope, potentially putting them at increasing risk from climate change. Flammulated owls in our study had a positive association with aspen, Douglas-fir, and to a lesser degree, ponderosa pine forests, and a negative association with lodgepole pine. They occupied sites (100-ha areas centered on the survey point) with higher canopy cover, moderate slope and roughness, located closer to ridgetops, and with higher probability of wildfire. Forests at over 15% of our sampled points have burned in the time since they were surveyed. In addition, our finding of a weak association with ponderosa pine forest may reflect changes due to fire suppression that in many areas may have degraded habitat quality of those forests for flammulated owls. We suggest that maps of the range and distribution for the species be updated to reflect our findings, specifically in western Wyoming, south-central Idaho, and southern California, which may impact planning for forest management in some areas. Furthermore, forest management actions to promote aspen restoration and regeneration, and to restore ponderosa pine stands to their historical structure and condition, may help this sensitive species adapt to impacts of climate change. Lastly, while this study covered a broad portion of the western United States, it did not cover several areas where flammulated owls are known to exist – Montana, Oregon, southern Utah, Nevada, Arizona, and New Mexico; we encourage further research in these areas.

中文翻译：

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美国西部繁殖季节火鸮的分布和栖息地关联

火鸮是一种小型食虫猫头鹰，在春季和夏季繁殖季节占据北美西部的森林。该物种尚未在其分布范围内得到广泛研究，但许多州、省和森林管理机构认为该物种敏感或处于危险之中。我们在西部多个州对该物种进行了有史以来最大规模的调查，以评估其分布和栖息地关联。2009年至2021年间，我们对3137个点完成了1至3次调查访问，并在309个（9.8%）个调查点发现了燃烧的猫头鹰。我们使用机器学习发生模型来估计栖息地关联。我们发现火猫头鹰的存在与特定的气候包络线密切相关，可能使它们面临越来越大的气候变化风险。在我们的研究中，火猫头鹰与白杨、花旗松和黄松森林呈正相关，在较小程度上与黄松森林呈正相关，与黑松呈负相关。他们占据的地点（以调查点为中心的100公顷区域）树冠覆盖度较高，坡度和粗糙度适中，靠近山脊顶部，发生山火的可能性较高。自调查以来，超过 15% 的采样点的森林都已被烧毁。此外，我们发现与黄松林的弱关联可能反映了由于灭火而发生的变化，在许多地区，灭火可能降低了这些森林中燃烧猫头鹰的栖息地质量。我们建议更新该物种的范围和分布地图，以反映我们的发现，特别是在怀俄明州西部、爱达荷州中南部和加利福尼亚州南部，这可能会影响某些地区的森林管理规划。此外，促进白杨恢复和再生以及将黄松林恢复到其历史结构和状况的森林管理行动可能有助于这种敏感物种适应气候变化的影响。最后，虽然这项研究覆盖了美国西部的大部分地区，但它并没有覆盖已知存在火猫头鹰的几个地区——蒙大拿州、俄勒冈州、犹他州南部、内华达州、亚利桑那州和新墨西哥州；我们鼓励在这些领域进行进一步研究。