We implemented a unique tree-climbing effort to examine nesting-habitat selection of Marbled Murrelets (Brachyramphus marmoratus) in managed forest stands of Washington and Oregon during 1996–1999. Researchers climbed over 3000 trees to search for old and active murrelet nests during the breeding season (May–Sept.) in a random sample of stands known to be occupied by murrelets. Within these stands, characteristics of murrelet nest sites and non-nest sites were measured at three fine spatial scales: nest limb or platform, nest tree, and nest-site or forest patch (0.5 ha). We report results of a Bayesian hierarchical logistic regression model using three covariates at each of the three fine spatial scales. All three branch/platform scale covariates positively predicted nest occupancy with higher probabilities of nesting occurring at branches/platforms with higher horizontal cover, larger platform diameters, and higher moss cover. Tree scale characteristics associated with higher probabilities of nesting included higher platform counts and higher moss depth. Effect of tree diameter on probability of nesting was unclear. At the patch scale, lower probability of nesting occurred for stands with higher densities of trees with platforms. This unexpected relationship may be due in part to decreasing likelihood of observing a nest on a given platform when there are more platforms in a patch. Variation in tree size and percent canopy cover at the patch scale showed no clear association with nest selection at the patch scale. The prevalence of nests in Dwarf Mistletoe-infected hemlock trees may have partially obfuscated the effect of tree diameter on probability of encountering a nest in portions of our study area. Fine scale conservation efforts for Marbled Murrelets may include recruiting or retaining trees with larger numbers of platforms, large branches with high percentages of moss cover and horizontal cover, and younger trees with platforms created by Dwarf Mistletoe deformities.

中文翻译：

---

三个精细空间尺度的大理石墨鱼巢选址

1996 年至 1999 年期间，我们实施了一项独特的爬树工作，以检查在华盛顿和俄勒冈州管理的林分中大理石海雀（Brachyramphus marmoratus）的筑巢栖息地选择。在繁殖季节（5 月至 9 月）期间，研究人员爬上 3000 多棵树，在已知被海雀占据的林分的随机样本中寻找古老而活跃的海雀巢穴。在这些林分内，在三个精细的空间尺度上测量了紫貂巢址和非巢址的特征：巢肢或平台、巢树和巢址或森林斑块（0.5 公顷）。我们在三个精细空间尺度中的每一个上使用三个协变量报告贝叶斯分层逻辑回归模型的结果。所有三个分支/平台规模协变量正预测巢穴占用率，在具有更高水平覆盖、更大平台直径和更高苔藓覆盖的分支/平台上筑巢的可能性更高。与更高的筑巢概率相关的树规模特征包括更高的平台数量和更高的苔藓深度。树木直径对筑巢概率的影响尚不清楚。在斑块尺度上，具有平台的树木密度较高的林分发生筑巢的可能性较低。这种意外的关系可能部分是因为当补丁中有更多平台时，在给定平台上观察巢穴的可能性会降低。斑块尺度下树木大小和冠层覆盖百分比的变化与斑块尺度上的巢穴选择没有明显关联。受矮槲寄生感染的铁杉树中巢穴的流行可能部分混淆了树木直径对我们研究区域部分地区遇到巢穴概率的影响。Marbled Murrelets 的精细保护工作可能包括招募或保留具有更多平台的树木、苔藓覆盖率和水平覆盖率高的大树枝，以及由矮槲寄生造成的平台的年轻树木。