International use of field boundary shrubs by a migratory warbler: cultural and agri-cultural considerations of farmers.

Abstract

The whitethroat (Sylvia communis) is a migratory warbler that is dependent on field boundary shrubs in both its breeding range (northern Europe) and wintering range (West Africa). This paper describes the management of this vegetation by farmers, and some influences on that management in both regions. In England, tall hedges are often regarded as of greater conservation value than low hedges, although whitethroats and some other species are more often associated with low hedges. Hedge location and a number of external influences determine the management of hedges by farmers and therefore their suitability for whitethroats. In Senegambia, whitethroats are associated with farmland shrub species such as Guiera senegalensis. Farmland shrubs were regarded as weeds and had little or no agronomic value to farmers. However, some have medicinal and cultural values. In addition, soil erosion and nutrient status are major problems for crop production and some shrub species used by warblers help to alleviate these problems.