Urban crows feed mainly on food wastes, also often dig up plantations and uproot grass in search of soil invertebrates, locally leading to extended damages to flower and lawn beds. Lethal methods to reduce crow numbers are largely inefficient, because of the large spatial scale of metapopulation dynamics. We tested experimentally if the mowing management of lawns could reduce grass uprooting by foraging crows in Paris during two consecutive years. Six lawn beds were mown as usual, six others remained unmown from September until February when we estimated the uprooted extend and the abundance of underground invertebrates. Unmowing led to taller grass, higher invertebrate abundances and a reduction of uprooting by 50%. It is ethically more acceptable than any lethal method, and provides economic benefits, by reducing the costs of lawn restoration, but also of mowing. We conclude that restricted mowing is ecologically, economically and ethically efficient to reduce grass uprooting by foraging urban crows.

Graphical abstract

中文翻译：

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限制割草减少了城市乌鸦将草连根拔起

城市乌鸦主要以食物垃圾为食，还经常挖掘种植园和拔草以寻找土壤中的无脊椎动物，从而对当地的花坛和草坪造成更大的破坏。由于集合种群动态的空间尺度很大，减少乌鸦数量的致命方法在很大程度上是低效的。我们通过实验测试了草坪的割草管理是否可以通过连续两年在巴黎觅食乌鸦来减少草连根拔起。六块草坪床照常修剪，另外六块草坪从 9 月到 2 月份仍未修剪，当时我们估计了被连根拔起的范围和地下无脊椎动物的数量。不割草导致草更高，无脊椎动物丰度更高，连根拔起的次数减少了 50%。从伦理上讲，它比任何致命的方法都更容易被接受，并通过降低草坪恢复的成本来提供经济利益，但也割草。我们得出的结论是，限制割草在生态、经济和伦理上都是有效的，可以通过觅食城市乌鸦来减少草连根拔起。

图形概要