Arable field margins managed for biodiversity conservation: A review of food resource provision for farmland birds

Most arable field margins are sown grass strips which are limited in the avian food resources they offer but potentially supply grass seeds and, depending on the complexity of the sward structure, a range of arthropods. Adding perennial forbs to a grass mixture provides more diverse plant and invertebrate food resources for birds. The availability of seeds and invertebrates on uncropped margins is strongly influenced by management, particularly cutting, cultivation and herbicide use. Cropped margins with reduced chemical inputs and wild bird cover crops can provide relatively high food resources compared with a conventionally managed crop. However, resources are only present until harvest, their plant communities are relatively poor and arthropod abundance is usually lower than in uncropped margins.