Woodland bird communities are immensely variable in the number and composition of species and the overall density. Some of this variation is essentially biogeographic. For example, the species pool in most taxonomic and ecological avian groups increases from Ireland through to central Europe (Fuller et al., 2007a). At more local scales, variation is driven mainly by environmental attributes that influence the resources available and consequently determine fitness of individual birds within habitat patches (Holmes, 1990; Chapter 2).

The context for this chapter is long-established woodland in landscapes that have been heavily populated and modified by people for hundreds, even thousands, of years. These woods are predominantly broadleaved, often with a recently introduced coniferous element. Mountain and conifer forests lie outside the scope of the chapter, but for a discussion of northern conifer forests see Chapter 19. In western Europe, a long history of human-related disturbance has produced woodland that is far removed from any ‘natural’ state. Historical interactions between socio-economic processes and environmental factors have produced great diversity of woodland types of varying habitat quality for birds. Regional traditions, differences in management systems and markets, spatial variation in grazing pressure, even neglect, all contribute to this heterogeneity. Whilst some heavily wooded landscapes have persisted, much woodland exists merely as fragments in agricultural landscapes and its plant and animal communities are strongly affected by the surroundings (Chapters 4–6).