Living on the edge: British and Irish woodland birds in a European context

Abstract

This paper reviews broad geographical patterns in the species composition of breeding woodland bird communities from Ireland to eastern Europe and outlines how processes affecting woodland birds in Britain and Ireland may differ from those operating in mainland Europe. Bird communities in British and Irish woodlands consist of a subset of the species occurring within European forests at similar latitudes. The occurrence of virtually all groups of forest birds is lower in Britain, and strikingly lower in Ireland, than in other temperate areas of mainland Europe. This phenomenon appears to form part of a west-east gradient in species diversity and is probably not just a consequence of insularity. Across this gradient there appears to be broad geographical constancy in the types (taxonomic, ecological and life-history groups) of species present. There is considerable spatial variation in habitat use by forest species within Europe. Some species in Britain probably use habitats in different ways to elsewhere for reasons related to competition, predation and historical adaptation to landscape change. Several species appear to reach the limits of their geographical ranges within Britain (i.e. in the absence of physical barriers). We suggest that range contraction of one of these species, the Common Nightingale Luscinia megarhynchos, in Britain may partially reflect redistribution into the highest quality areas in response to a wider population decline. It is argued that conclusions drawn from studies of forest birds in Britain do not necessarily apply in other regions and vice versa. There is a need for large-scale studies in Europe of the spatial variation in organization of forest bird assemblages, habitat use and the genetic structure of populations. © 2007 The Authors.