Grassland bird populations are declining faster than any other avian guild in North America, and promotion of favorable habitat conditions in rangeland breeding cores is important for their maintenance. There is much information on associations between breeding grassland songbirds and vegetation attributes. However, previous results have been difficult to translate into management practices due to mismatch between the scale and metrics used in biological sampling and those used in management. Here, we evaluate the response of imperiled grassland bird species to vegetation conditions using metrics and scales accessible to managers. We focus on four species that are experiencing particularly severe population declines: Baird's sparrow (Centronyx bairdii), chestnut-collared longspur (Calcarius ornatus), McCown's longspur (Rynchophanes mccownii), and Sprague's pipit (Anthus spragueii). In 2017 and 2018, we evaluated the abundances of these species within their core distributions in northern Montana. We used temporally replicated point-counts and hierarchical models to estimate abundance and associations with plot-level (9-ha) vegetation conditions while accounting for spatially and temporally variable detectability. Exotic grass encroachment and shrub cover had negative or neutral effects on all species. Birds responded strongly to biomass at this scale, with chestnut-collared longspurs and Sprague's pipit preferring a range of 1 100 kg ha⁻¹ to 1 400 kg ha⁻¹, and McCown's longspurs selecting for the lowest available. Residual grass and litter cover were important for Baird's sparrows. Variable results among species emphasize the need for heterogeneity in vegetation structure and composition at scales larger than the plot. Our results provide guidance for managers interested in improving habitat for these species.

草原鸟类的数量下降速度比北美任何其他鸟类协会都要快，促进牧场繁殖核心的有利栖息地条件对其维护至关重要。关于繁殖草地鸣禽与植被属性之间的关联的信息很多。但是，由于生物采样所使用的规模和指标与管理所使用的规模和指标不匹配，以前的结果很难转化为管理实践。在这里，我们使用管理者可以访问的度量标准和尺度来评估受威胁的草原鸟类物种对植被状况的响应。我们关注四种种群下降特别严重的物种：贝尔德的麻雀（Centronyx bairdii），栗领长突（Calcarius ornatus）， McCown的长刺（Rynchophanes mccownii）和Sprague的pi（Anthus spragueii）。在2017年和2018年，我们在蒙大拿州北部的核心分布范围内评估了这些物种的丰度。我们使用时间复制的点数和层次模型来估计丰度和与地块级（9公顷）植被状况的关联，同时考虑到时空可变的可检测性。外来草种的侵占和灌木覆盖对所有物种均具有负面或中性影响。鸟类对这种规模的生物量反应强烈，板栗领长马刺和斯普拉格（Sprague）的田pit更倾向于1100 kg ha ^-1至1400 kg ha ^-1的范围，而麦考恩（McCown）的长刺则选择最低的马刺。残留的草和垃圾覆盖物对于Baird的麻雀很重要。物种间的可变结果强调了在大于地块的尺度上需要植被结构和组成的异质性。我们的结果为有兴趣改善这些物种栖息地的管理人员提供了指导。