Generalist species – with their wide niche breadths – are often associated with urban environments, while specialist species are likely to be most at‐risk of increasing urbanization processes. But studies which quantify the relationship between trait specialization (i.e. niche breadth) and urban tolerance are generally methodologically limited, with repeatable robust methods to easily quantify this relationship among different regions and time scales often lacking. Our objective was to use novel methods to quantify the relationship between trait specialization and urban tolerance over a broad spatial scale. We used ~ 2 million citizen science observations and spatially intersected these with remotely‐sensed VIIRS night‐time light values and a novel continuous measure of a species’ trait specialization for 256 European bird species. We found a negative relationship between avian urban tolerance and an overall specialization index. Nesting site niche breadth was especially negatively associated with higher urban tolerance scores. Our results highlight that species with a high degree of trait specialization likely have a lower capacity to persist in urban ecosystems, and hence, could be most at‐risk in novel urban ecosystems. We suggest that trait specialization can be used as a proxy for the degree of risk posed by urban environments to a given species.

中文翻译：

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禽类特征专业化与城市耐受性负相关

通才物种（具有广泛的利基广度）通常与城市环境有关，而专业物种则可能是城市化进程不断增加的最大风险。但是，量化特质专业化（即利基宽度）与城市容忍度之间关系的研究通常在方法上是有限的，可重复使用的鲁棒方法很难轻松量化不同地区和时标之间的这种关系。我们的目标是使用新颖的方法在广泛的空间范围内量化特征特化与城市容忍度之间的关系。我们使用了约200万种公民科学观测，并将它们与遥感VIIRS夜间光值在空间上相交，并对256种欧洲鸟类的物种特征进行了新颖的连续测量。我们发现禽类城市耐受性与总体专业化指数之间存在负相关关系。筑巢地点的利基广度尤其与较高的城市耐受性得分负相关。我们的研究结果表明，具有较高性状专业化水平的物种在城市生态系统中的持久能力可能较低，因此，在新型城市生态系统中其风险最高。我们建议，性状专业化可以用作城市环境对给定物种构成的风险程度的替代。因此，在新的城市生态系统中可能会面临最大的风险。我们建议，性状专业化可以用作城市环境对给定物种构成的风险程度的替代。因此，在新的城市生态系统中可能会面临最大的风险。我们建议，性状专业化可以用作城市环境对给定物种构成的风险程度的替代。