Cities are designed for humans but are also highly dynamic ecosystems that provide habitats for wild animals. These habitats depend on a city's green infrastructure which is increasingly threatened by urban densification. A commonly studied model taxon for wild animals in cities are birds, and the importance of large green spaces for the diversity of birds in cities has been shown. However, how small-scale green spaces affect bird communities, which local characteristics are important, and whether there are seasonal differences remains unclear. We asked how and to what extent the characteristics of city squares in Munich affect the diversity and abundance of birds and if there are differences between bird communities in spring, autumn, and winter. We monitored birds on 103 city squares in Munich using a search-route method. Sampled squares spanned a spatial gradient from the center to the periphery of the city and differed in sealed surface proportion and vegetation structures, such as trees, shrubs, and lawns. The diversity and abundance of birds increased with a higher proportion of green characteristics on the square. Especially the proportion of grass cover and the density of trees had strong positive effects. Old trees had additional effects on birds beyond the effects of trees in general, while the mean number of people on a square negatively influenced bird abundance and diversity. Despite seasonal changes in bird composition, square characteristics showed consistent effects on bird abundance and diversity over seasons. These results underline that the green characteristics of city squares, and therefore of small-scale green spaces, affect their suitability as habitat for wildlife in cities. Integrating this knowledge into city planning can help to maintain or even increase urban biodiversity in the future.

城市是为人类设计的，但同时也是高度动态的生态系统，为野生动物提供栖息地。这些栖息地依赖于城市的绿色基础设施，而城市的绿色基础设施日益受到城市密集化的威胁。一个普遍研究的城市野生动物模型分类群是鸟类，大型绿地对城市鸟类多样性的重要性已被证明。然而，小规模的绿地如何影响鸟类群落，哪些地方特征很重要，以及是否存在季节性差异，尚不清楚。我们询问慕尼黑城市广场的特征如何以及在多大程度上影响鸟类的多样性和丰度，以及春季、秋季和冬季鸟类群落之间是否存在差异。我们使用搜索路线方法监测了慕尼黑 103 个城市广场上的鸟类。采样的广场跨越了从城市中心到外围的空间梯度，密封面比例和植被结构不同，如乔木、灌木和草坪。鸟类的多样性和丰富度随着广场上绿色特征比例的增加而增加。特别是草覆盖比例和树木密度有很强的积极作用。老树对鸟类的影响超出了一般树木的影响，而广场上的平均人数对鸟类的数量和多样性产生了负面影响。尽管鸟类组成有季节性变化，但方形特征对鸟类的丰度和多样性在季节中表现出一致的影响。这些结果强调了城市广场以及小规模绿地的绿色特征，影响它们作为城市野生动物栖息地的适宜性。将这些知识整合到城市规划中有助于在未来维持甚至增加城市生物多样性。